Description Trichoblastomas are uncommon adnexal tumors that usually occur on the face. We report a case of a 62-year-old White man with a large, asymptomatic, slow-growing lesion that had been on his right upper cutaneous lip for 15 years. A 2 cm pink, pedunculated nodule with telangiectasia was seen on examination. A shave biopsy was consistent with trichoblastoma: a circumscribed-appearing dermal tumor of basaloid cells arranged in cords and islands within a cellular stroma, focal epidermal connection, and papillary mesenchymal bodies. The patient elected for treatment with Mohs micrographic surgery (MMS) given the length of time that the tumor had been neglected as well as its large size, location in cosmetically sensitive area, and ability to deeply invade beyond clinical margins. The tumor was cleared after 2 stages, and a rotation flap was performed. Approximately 2 months later, the patient had achieved excellent cosmesis and was satisfied with the surgical outcome. This case highlights the utility of MMS to treat large (and in our case, neglected) facial trichoblastomas. Despite being benign tumors, trichoblastomas that are large and long-standing may have improved outcomes with MMS, especially given their ability to invade deeply beyond clinical margins. As a result of MMS, patients with large facial trichoblastomas can achieve tumor clearance and the best possible cosmetic outcome.

The pigmented lesion assay (PLA) is a noninvasive test used to risk stratify pigmented lesions and rule out melanoma. There is a scarcity of data from nonbiased studies on PLA performance in the real world. PLA results from 107 skin specimens were compared with final pathologic diagnoses. To determine clinical relevance of PLA results, diagnoses were categorized into actionable melanocytic, nonactionable melanocytic, and nonmelanocytic. Of specimens with positive PLA results, 24.0% (25/104) were actionable melanocytic diagnoses, 42.3% (44/104) nonactionable melanocytic, and 33.7% (35/104) nonmelanocytic. Because most specimens submitted for pathologic evaluation had positive PLA results, positive predictive values were calculated for overall PLA results and the individual genes tested. The overall positive predictive value for surgically actionable melanocytic lesions was 24.0%. The positive predictive values of the individual genes were determined to be 28.2% for LINC00518, 34.7% for PReferentially expressed Antigen in Melanoma, and 31.8% for telomerase reverse transcriptase.

Background:Endometriosis is a common condition in which endometrial glands and stroma are implanted outside the uterine cavity. Rarely, the skin can be involved. Case Presentation:We describe a case of a 41-year-old woman who presented to the dermatology clinic complaining of a brown umbilical nodule with slight erythema. It was occasionally painful and hemorrhagic. She denied a history of endometriosis and abdominal surgeries. A shave biopsy of the nodule was consistent with a diagnosis of cutaneous endometriosis. The patient was referred to her gynecologist for further evaluation and treatment. Conclusion:This unique case demonstrates primary cutaneous endometriosis in the umbilicus of a female patient. Cutaneous endometriosis can be classified as primary or secondary. Primary cutaneous endometriosis is rarer and has an unclear etiology, developing seemingly spontaneously without history of surgical interventions. Secondary cutaneous endometriosis typically arises within surgical scars following abdominal operations, which is believed to be a result of iatrogenic implantation of endometrial cells. Definitive treatment involves surgery. This case highlights the importance of considering cutaneous endometriosis in the differential diagnosis of a female patient with painful and intermittently hemorrhagic skin nodules.

BACKGROUND:Due to perceived difficulty in the categorization of angioinvasive fungal infections based on histopathology, variation exists in dermatopathology reporting.METHODS:This study characterized the diagnosis of angioinvasive fungal infections by light microscopy at a single academic institution over an 11-year period. Subsequently, the accuracy of blinded reclassification by virtual microscopy was measured.RESULTS:Seventy-six specimens with hematoxylin-eosin slides were obtained from 33 patients. The mean diagnostic accuracy of dermatopathologists in differentiating mucormycosis, hyalohyphomycosis, and phaeohyphomycosis based on blinded reclassification via virtual microscopy was 74%, with a range of 65%-91%.CONCLUSIONS:While there was a range in diagnostic accuracy, the highest score of 91% and the identification of common sources of error suggest that histopathologic categorization of angioinvasive fungal infections can frequently be performed. However, accurate identification is not always possible given common pitfalls in diagnosis. In addition, standardized and clinically useful reporting should be considered.

Non-uremic calciphylaxis (NUC) is a rare, high-mortality disease, and it can be easily misdiagnosed as other ulcerative dermatologic conditions. A female in her late 30s with a medical history of alcoholic liver cirrhosis and obesity who previously underwent gastric bypass surgery presented with an 11-month history of worsening bilateral lower extremity wounds following the initiation of spironolactone. A wound biopsy at the time of initial presentation favored erythema multiforme/toxic epidermal necrolysis (EM/TEN). She initially responded to systemic steroids, but her wounds later worsened, prompting her to seek representation a few months later. The initial suspicion was for a superimposed bacterial infection; however, her wounds did not improve following antibiotics. A repeat skin biopsy revealed calciphylaxis, for which she had multiple risk factors, including severe vitamin D deficiency causing secondary hyperparathyroidism. A multidisciplinary approach was successful in achieving a satisfactory response with pain control, wound care, skin grafting, and mitigation of risk factors in addition to the use of sodium thiosulfate. Upon our review, the initial biopsy did not demonstrate features of EM/TEN but did demonstrate features suspicious for calciphylaxis. The exposure to systemic corticosteroids due to the presumed diagnosis of EM/TEN may have worsened her condition since this is a known risk factor for calciphylaxis. Our case highlights the importance of clinicopathologic correlation as well as the place for calciphylaxis in the clinical and histopathologic differential diagnosis of ulcerated, necrotic lesions on the lower extremities in the absence of renal disease.

Background: A 62-year-old white male with no reported dermatological history presented to our clinic complaining of an asymptomatic, slow-growing lesion on his face that had been present for 15 years. On examination, a 2 cm pink, pedunculated nodule with telangiectasia was observed on his right upper cutaneous lip. A shave biopsy was performed. The specimen was sent for histological evaluation, which was consistent with the diagnosis of trichoblastoma. Given the tumor's large size, location in cosmetically-sensitive area, and ability to deeply invade and extend beyond clinical margins, the patient elected for treatment with Mohs micrographic surgery (MMS). The tumor was cleared after two stages of MMS. A rotation flap was performed to repair the surgical defect. Approximately two months after the procedure, the patient had achieved excellent cosmesis and was satisfied with the surgical outcome.

Herpes simplex virus type II (HSV-II) with superimposed bacterial skin infection is an uncommon presentation of cutaneous necrosis in the setting of infective endocarditis. This case reflects a unique presentation of an immunosuppressed patient with infective endocarditis complicated by septic emboli and cutaneous skin lesions attributable to HSV-II and superimposed bacterial skin infection. The patient presented from an outside hospital with symptoms consistent with acute onset heart failure and skin lesions. Transthoracic and transesophageal echocardiography performed there demonstrated focal thickening of the anterior mitral valve leaflet with severe mitral regurgitation. The patient then underwent extensive infectious work-up and was put on broad-spectrum antibiotics. Further work-up demonstrated greater than three DUKE minor criteria and reiterated the focal thickening of the anterior leaflet of the mitral valve, making infective endocarditis the most likely etiology. Biopsies of the skin lesions were performed which stained positive for HSV-II and grew methicillin-resistant Staphylococcus aureus and Bacteroides fragilis. The cardiothoracic surgery service ultimately decided not to perform any surgical intervention to the mitral valve during her hospitalization as she was deemed to be too high of a risk due to her thrombocytopenia and significant comorbidities. She was later discharged in hemodynamically stable condition on long-term intravenous antibiotics with repeat echocardiography demonstrating significant reduction in the mitral regurgitation and the focal thickening of the anterior leaflet of the mitral valve.

A woman in her 40s presented to the emergency department with a diffuse rash consistent with Stevens -Johnson syndrome (SJS). There was no identifiable inciting factor. However, she was newly diagnosed with human immunodeficiency virus (HIV) during that same hospital admission. The leading theory for why she developed SJS given her lack of classic precipitating factors is an immune dysregulation as a result of HIV. Most cases of SJS/toxic epidermal necrolysis (TEN) in patients with HIV are related to highly active antiretroviral therapy and prophylaxis with trimethoprim-sulfamethoxazole. There is a lack of literature regarding SJS as the initial presentation of HIV without known underlying etiology or inciting factors.

Background: Histopathology protocols for processing dermatopathology specimens vary among laboratories.Objective: To determine an optimal histopathology protocol to minimize cost and turnaround time (TAT) for biopsy specimens in a dermatopathology laboratory.Methods: A prospective, 4-month study compared the mean cost and TAT of pro-ducing one versus two initial H & E slides, and zero versus three unstained slides that could be used for frequently used special or immunohistochemical (IHC) stains.Results: For all cases, cost was lower for one versus two initial H & E slides, with an insignificant increase in TAT. Producing three vs zero unstained slides incurred higher cost, with no reduction in TAT. In a subset of cases in which frequently used special or IHC stains were performed, cost and TAT were optimized by producing one initial H & E and three unstained slides. Conclusion: A protocol of one initial H & E slide and zero unstained slides optimizes cost and TAT in our dermatopathology laboratory. Pigmented lesions and inflamma-tory dermatoses may benefit from the addition of unstained slides. Further study is needed to quantify this benefit and evaluate for other cases for which an alternative protocol is advantageous.

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer that presents most frequently on the head and neck of elderly Caucasian males. Its morphology can be variable, but it most commonly appears as a rapidly growing, erythematous to violaceous cutaneous nodule. This condition is associated with a number of risk factors, including chronic ultraviolet exposure, advanced age, immunosuppression, and Merkel cell polyomavirus (MCPyV).1 Although rare, MCC has been increasing in frequency over the last few decades, with an estimated incidence in the United States of 3 per million per year.

A 13-year-old male was evaluated for possible scalp infection. The patient's mother reported white scaly patches on the scalp and red rash on the patient's body folds and genitals for multiple years. She described a strong family history of hereditary mucoepithelial dysplasia (HMD) in herself, multiple maternal aunts and uncles, and maternal grandfather, and stated that the family had been studied and described in a publication by Witkop et al in 1979. Physical examination revealed coalescing patches of alopecia involving the entire scalp and bilateral eyebrows with a background of white scaly plaques. Residual hairs appeared thin and brittle (Figure 1). Bright red, welldefined, psoriasiform plaques in scrotal and intertriginous areas, as well as thin pink to red plaques involving all dorsal proximal interphalangeal joints, were observed. Generalized xerosis with follicular prominence was observed. Based on the clinical presentation and strong family history, a diagnosis of HMD was made. A shave biopsy specimen from the patient's scalp, recently performed at an outside institution, was reviewed. The shave biopsy specimen showed psoriasiform epidermal acanthosis with foci of subtle papillomatosis and overlying orthokeratosis. Slight invaginations of the epidermis with loss of the granular layer, collections of dyskeratotic cells, and overlying columns of parakeratosis resembling coronoid lamellae were present. Similar foci of dyskeratosis with parakeratotic plugging were present in follicular infundibula (Figure 2A, B). A decreased density of hair follicles was observed with both empty follicles and follicles with fractured hair shafts. Follicles appeared dilated or distorted, and perifollicular fibroplasia with lymphohistiocytic inflammation and with rare eosinophils was present at the level of the follicular infundibulum (Figure 2C). Dermal fibrosis and a decreased density of sebaceous glands were observed. Although complete assessment was limited to shave biopsy technique, additional punch biopsy of the child's scalp was performed given the limited impact it would have on management.

Spotted fever group rickettsiae (SFGR) represent gram-negative intracellular bacteria transmitted to human hosts through tick bites.1,2 Although Rocky Mountain spotted fever (RMSF) represents the prototypical rickettsiosis associated with SFGR, this group also includes Rickettsia parkeri. Among the SFGR, R parkeri may produce a distinct vesicular eruption preceded by an eschar. Thus, R parkeri rickettsiosis may clinically and histopathologically simulate rickettsialpox due to Rickettsia akari. Herein, we present a case of vesicular spotted fever due to R parkeri.

Eccrine syringofibroadenoma (ESFA) is a rare cutaneous adnexal lesion of eccrine duct origin, first described by Mascaro in 1963.1 It remains controversial as to whether it is a true neoplastic process, hamartoma, or reactive eccrine hyperplasia. Multiple ESFA, also known as eccrine syringofibroadenomatosis, is an unusual variant of ESFA that has been primarily described in reported cases as palmoplantar hyperkeratosis.2-6 Because of its rarity, ESFA is not often recognized and may be difficult to distinguish from more common inflammatory dermatoses, which may lead to inappropriate therapeutic interventions.

: The number of skin biopsies has increased over the last three decades, but benchmarks based on the number of biopsies required to capture skin cancers are lacking. To determine the most common dermatopathology diagnoses, reports of all 85,785 dermatopathology specimens examined in the Department of Dermatology at the University of Florida from January 2017 to December 2017 were reviewed. 78,353 non-excisional specimens were evaluated for diagnosis. 7,432 excisional specimens consisting of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), melanoma, and dysplastic nevi were evaluated for residual tumor and marginal status. The fifteen most common diagnoses accounted for 84% of all biopsies, and an additional 30 entities accounted for 12% of all biopsies. The remaining 4% of cases were composed of only 206 diagnoses. This pattern reflects current dermatology practice in the United States, wherein the 20 most commonly encountered diseases account for 85.4% of all diagnoses made by dermatologists. Among the total number of biopsies, 90.7% of specimens were neoplasms and 9.3% were inflammatory or infectious disorders. Uncommon (4%) and inflammatory or infectious (9.3%) disorders comprise a small minority of academic dermatopathology, with implications for resident and fellowship training.

The authors have no conflicts of interest to declare. Prior presentation: A poster abstract of this work was presented at the 55th American Society of Dermatopathology, November 9, 2018 in Chicago, IL.

Epidermotropic metastases from colorectal adenocarcinoma are very uncommon. Frequently, these metastases appear within 2 years after resection of the primary tumor and just like renal, breast, ovarian, and bladder cancer, disseminate to the skin through lymphatic and blood. The early recognition of cutaneous metastases establishes the management and prognosis for the patient by indicating a potential relapse. Less frequently, these findings are the first manifestation of the malignancy, facilitating an immediate therapeutic action.

Background: Lichenoid granulomatous dermatitis (LGD) is an uncommon reaction pattern for which clinical correlates can be difficult to establish. LGD combines vacuolar degeneration with variable types of granulomas. Objective: To determine clinical correlates of LGD. Methods: The laboratory information systems at the University of Florida, the Medical College of Wisconsin, and Inform Diagnostics Research Institute were queried to identify 56 cases of LGD. Cases were reviewed for information regarding eosinophils, plasma cells, deep perivascular infiltrates, granuloma subtype, parakeratosis, epidermal atrophy, psoriasiform epidermal changes, pseudoepitheliomatous hyperplasia, periadnexal inflammation, vasculitis, and red blood cell extravasation. Results: The most common clinical correlates were drug eruption (39.3%, n = 22) and lichenoid keratosis (19.6%, n = 11). Tattoo reaction, postherpetic dermatitis, and scabies or postscabietic dermatitis each accounted for 7.1% (n = 4) of cases. Pigmented purpuric dermatosis and lichen striatus each accounted for 5.4% (n = 3) of cases. Dermal eosinophils (P = .005) and psoriasiform epidermal changes (P = .055) were associated with drug hypersensitivity. Perineural (P = .049) and perifollicular (P = .003) inflammation were associated with tattoo reaction and postherpetic dermatitis. Red blood cell extravasation was helpful in cases of pigmented purpuric dermatosis (P = .049). Limitations: This study is limited by its retrospective nature and statistical power. Conclusion: Dermal eosinophilia, psoriasiform epidermal changes, periadnexal inflammation, and red blood cell extravasation might aid in the clinical diagnosis of patients with LGD.

To the Editor: Rowell syndrome is characterized by erythema multiforme–like lesions with serologic and historical evidence of lupus erythematosus (LE).1Torchia D. Romanelli P. Kerdel F.A. Erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis associated with lupus erythematosus.J Am Acad Dermatol. 2012; 67: 417-421Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar Classification of Rowell syndrome remains controversial, given overlapping clinical features of erythema multiforme and cutaneous LE (CLE).2Rowell N.R. Beck J.S. Anderson J.R. Lupus erythematosus and erythema multiforme-like lesions. A syndrome with characteristic immunological abnormalities.Arch Dermatol. 1963; 88: 176-180Crossref PubMed Scopus (181) Google Scholar Our objective was to identify histologic and immunohistochemical findings that support classification of Rowell syndrome because current definitions lack these criteria.3Zeitouni N.C. Funaro D. Cloutier R.A. et al.Redefining Rowell's syndrome.Br J Dermatol. 2000; 142: 343-346Crossref PubMed Scopus (113) Google Scholar CD123, which labels pathogenic plasmacytoid dendritic cells in LE, might be useful in this context.4Swiecki M. Colonna M. The multifaceted biology of plasmacytoid dendritic cells.Nat Rev Immunol. 2015; 15: 471-485Crossref PubMed Scopus (659) Google Scholar, 5Vermi W. Lonardi S. Morassi M. et al.Cutaneous distribution of plasmacytoid dendritic cells in lupus erythematosus. Selective tropism at the site of epithelial apoptotic damage.Immunobiology. 2009; 214: 877-886Crossref PubMed Scopus (115) Google Scholar After institutional review board approval, the archives of the University of Florida and Inform Diagnostics were queried for diagnoses of Rowell syndrome (8 biopsies from 5 patients), subacute CLE (SCLE, 7 biopsies from 4 patients), and erythema multiforme (5 biopsies from 5 patients) rendered during November 2016-June 2018; an additional single indeterminate case was also identified. Clinical features, serology, histology, and CD123 antibody staining for plasmacytoid dendritic cells were compared between Rowell syndrome, SCLE, and erythema multiforme cases after a blinded retrospective histologic review. A Fisher's exact test was used to compare histologic variables and CD123 staining patterns among Rowell syndrome, SCLE, and erythema multiforme cases. Two-tailed P values <.05 were deemed statistically significant. Rowell syndrome and SCLE were characterized by female predominance, antecedent history of LE, lack of causative medication, absence of mucosal involvement, positivity for rheumatoid factor, and speckled antinuclear antibody pattern with anti-Ro (SS-A) positivity (Table I). Targetoid plaques were observed in Rowell syndrome (4/4) but not SCLE (0/4). Conversely, anti-La (SS-B) positivity was observed in SCLE (2/3) but not in Rowell syndrome (0/4), which might reflect variable assay sensitivity for the detection of this autoantibody.6Franceschini F. Cavazzana I. Anti-Ro/SSA and La/SSB antibodies.Autoimmunity. 2005; 38: 55-63Crossref PubMed Scopus (178) Google Scholar Direct immunofluorescence was positive in Rowell syndrome (1/1) and SCLE (1/1) but negative in erythema multiforme (0/1). Summarized in Table I, the common and unifying histologic features of Rowell syndrome (Fig 1) and SCLE (Figure 2; available at https://data.mendeley.com/datasets/bwswc4h9yb/1) include periadnexal lymphocytic infiltrates (P = 1), absence of dermal eosinophils (P = 1), and CD123 positivity of ≥10% of the inflammatory infiltrate (P = 1). Distinction of Rowell syndrome from erythema multiforme (Figure 3; available at https://data.mendeley.com/datasets/bwswc4h9yb/1) can be supported by periadnexal lymphocytic infiltrates (P = .003) and periadnexal CD123+ plasmacytoid dendritic cells (P = .049). Using these features, the indeterminate case was reclassified as Rowell syndrome. Several features did not aid classification (1 > P > .05), including interface tissue reaction subtype (lichenoid or cell poor), deep perivascular lymphocytic infiltrates, periadnexal plasmacellular aggregates, mucin deposition (by Alcian blue staining), and the predominant CD123 staining pattern (epidermal or dermal).Table IComparison of RS, SCLE, and EM by clinical, serologic, histologic and immunohistochemical findingsCharacteristic or findingRS (5 patients; 8 biopsies)SCLE (4 patients; 7 biopsies)EM (5 patients; 5 biopsies)RS and SCLE, P valueRS, SCLE, and EM, P valueAge, y, mean ± standard deviation53 ± 23.1562.8 ± 16.4452.8 ± 16.07Female sex80 (4/5)100 (4/4)80 (4/5)11History of LE∗History of systemic or cutaneous LE.100 (4/4)75 (3/4)0 (0/5)1.0047Targetoid lesions†≥2 zones of color.100 (4/4)0 (0/4)100 (5/5).0286.0028Mucosal involvement0 (0/4)0 (0/4)40 (2/5)1.2821Implicated medication0 (0/4)0 (0/4)20 (1/5)11Speckled antinuclear antibody pattern50 (2/4)67 (2/3)0 (0/2)1.5238Lesional direct immunofluorescence‡Granular deposition of IgG in the lower epidermis along the basement membrane zone, with an antinuclear antibody pattern in keratinocytes. Granular deposition of IgM, IgA, and complement C3 and C5b-9 along the basement membrane zone.100 (1/1)100 (1/1)0 (0/1)11Full-thickness epidermal necrosis50 (4/8)0 (0/7)80 (4/5).077.017Parakeratosis25 (2/8)85.7 (6/7)20 (1/5).041.034Dermal eosinophils0020 (1/5)1.250Periadnexal lymphocytic infiltrate§Perifollicular or perieccrine.87.5 (7/8)85.7 (6/7)01.003≥10% CD123+ cells¶Percentage of inflammatory cells positive for antibody staining in a single histologic section.62.5 (5/8)57.1 (4/7)20 (1/5)1.395Dermal-predominant CD123 pattern42.9 (3/7)83.3 (5/6)40 (2/5).266.292Intraepidermal CD123+ plasmacytoid DCs100 (7/7)66.7 (4/6)100 (5/5).192.163Periadnexal CD123+ plasmacytoid DCs100 (7/7)66.7 (4/6)40 (2/5).192.049Values are % (n/total) except where indicated. Significant values are in bold.DCs, Dendritic cells; EM, erythema multiforme; LE, lupus erythematosus; RS, Rowell syndrome; SCLE, subacute cutaneous lupus erythematosus.∗ History of systemic or cutaneous LE.† ≥2 zones of color.‡ Granular deposition of IgG in the lower epidermis along the basement membrane zone, with an antinuclear antibody pattern in keratinocytes. Granular deposition of IgM, IgA, and complement C3 and C5b-9 along the basement membrane zone.§ Perifollicular or perieccrine.¶ Percentage of inflammatory cells positive for antibody staining in a single histologic section. Open table in a new tab Values are % (n/total) except where indicated. Significant values are in bold. DCs, Dendritic cells; EM, erythema multiforme; LE, lupus erythematosus; RS, Rowell syndrome; SCLE, subacute cutaneous lupus erythematosus. This series is limited by its small sample size, retrospective nature, and lack of complete clinical data for all patients. Previously dependent on clinical history, serology, and nonspecific clinical morphology, diagnosis of Rowell syndrome might be improved by histologic detail and CD123 staining. Unifying features of Rowell syndrome and SCLE include antecedent history of LE, absence of mucosal involvement, serology (antinuclear antibody, anti-Ro, and rheumatoid factor), direct immunofluorescence positivity, periadnexal lymphocytic infiltrates, absence of dermal eosinophils, and CD123+ inflammatory cells only when comprising ≥10% of the inflammatory infiltrate. In the context of targetoid clinical morphology, this feature aids in the distinction of Rowell syndrome from erythema multiforme. These clinicopathologic findings support inclusion of Rowell syndrome in the spectrum of CLE and provide therapeutic or prognostic benefit to patients with diagnoses previously identified as Rowell syndrome or erythema multiforme.