Eccrine syringofibroadenoma (ESFA) is a rare adnexal proliferation of acrosyringeal origin. Multiple, diffuse palmoplantar ESFA (eccrine syringofibroadenomatosis) is a recognized cutaneous marker of Schöpf–Schulz–Passarge syndrome (SSPS), a WNT10A-related ectodermal dysplasia, although ESFA-like changes may also arise reactively in chronic inflammatory dermatoses. We report a 66-year-old woman with a 10-year history of palmoplantar lesions clinically diagnosed as psoriasis and refractory to topical therapy, acitretin, adalimumab and ixekizumab. She also had long-standing diffuse alopecia and recurrent eyelid margin lesions previously treated with electrocoagulation. Examination showed erythematous, desquamative and fissured palmoplantar plaques, diffuse non-scarring alopecia and multiple cysts along both eyelid margins. Because of treatment failure and this atypical constellation, a palmoplantar biopsy was performed, revealing a reticulated eccrine syringofibroadenomatous (ESFA-like) proliferation with dilated eccrine ducts. This histological clue, interpreted together with keratoderma, hypotrichosis and eyelid margin cysts (the core features of SSPS), prompted targeted genetic testing, which identified a homozygous pathogenic WNT10A variant, c.321C>A p.(Cys107*), confirming SSPS. Apremilast 30 mg twice daily was followed by improvement in erythema, scaling and fissuring maintained after 24 months of follow-up. This case shows how recognition of ESFA-like changes in a biopsy from presumed refractory palmoplantar psoriasis, together with subtle ectodermal signs, can uncover SSPS in adulthood.
Background/Objectives: Pigmented lesions arising at sites of remote trauma can create diagnostic uncertainty when their clinical appearance overlaps with melanocytic neoplasms. This report describes a graphite foreign-body granuloma presenting decades after a childhood pencil injury and highlights the importance of distinguishing exogenous pigment from melanocytic proliferation. Methods: A 64-year-old man presented with an asymptomatic 6-mm blue dermal nodule on the left fifth digit at the site of a penetrating pencil injury sustained during childhood. After remaining unchanged for decades, the lesion gradually enlarged over three years and produced mild nail plate deformity without periungual or subungual pigmentation. Cellular blue nevus, nodular melanoma, and graphite foreign-body granuloma were considered. A shave biopsy was performed, followed by histopathologic examination. Results: The biopsy revealed a well-demarcated intradermal lesion containing abundant dark amorphous pigment and sclerosis. Higher-power examination demonstrated coarse granular black pigment associated with multinucleated giant cells and surrounding fibrosis, without melanocytic proliferation. These findings established the diagnosis of graphite foreign-body granuloma. Conclusions: Retained graphite may produce a delayed foreign-body reaction and become clinically concerning many years after implantation. Because its clinical features may overlap with melanoma and other pigmented tumors, a history of remote trauma can refine the differential diagnosis but cannot replace tissue examination. Histopathologic evaluation remains essential for definitively distinguishing exogenous pigment from melanocytic proliferation.
Collision tumors are exceptionally rare. We report here a case of a cutaneous collision tumor composed of metastatic melanoma and small lymphocytic lymphoma (SLL). A 56-year-old man with a prior history of melanoma and chronic lymphocytic leukemia (CLL) presented with a new cutaneous nodule near the previous melanoma excision site on the right lower flank. Imaging identified a separate skin lesion in the right medial thigh. Histopathologic examination of both lesions revealed an infiltrative malignant melanoma in the flank and a melanoma with similar morphology in the medial thigh, adjacent to a dense, monotonous lymphoid infiltrate involving the subcutis and skeletal muscle. Immunohistochemical studies demonstrated that the melanoma cells were positive for SOX10, MART-1 and cyclin D1; the lymphoid population was positive for CD5, CD20, PAX5 and CD23, and negative for CD3, CD10 and cyclin D1. Given the known history, the combined morphologic and immunophenotypic findings support the diagnosis of a cutaneous collision tumor composed of melanoma and SLL/CLL. A review of the literature highlights the rarity of such cases and sheds light on current theories of pathogenesis, diagnostic pitfalls, and the mainstay treatment of this rare collision tumor.
Histologic submission and processing of nail unit specimens require special attention, primarily because of the contrast between the hard plate and the delicate matrix/bed tissue. Adherence of the plate to the glass slide is particularly challenging, and a protocol is included to address this challenge. Loss of the often small, fragile matrix/bed tissue can lead to absence of histopathologic features needed to make a definitive diagnosis. Of primary importance is the submission of matrix/bed specimens, which are often small and fragmented on a paper template of a nail, which is then placed securely in a tissue cassette between sponges, thereby preserving tissue orientation and allowing for flat fixation for a minimum of 8 h. Immunostains and other special stains also differ somewhat from their use elsewhere on the skin, the details of which are presented.
Skin biopsy is one of the most valuable diagnostic procedures in dermatology, particularly when clinical findings alone are insufficient to establish a diagnosis. However, obtaining an accurate histopathological diagnosis depends on multiple steps, and errors at any stage of the biopsy pathway may compromise the final result. This review synthesizes current evidence and available guidelines on best practices for skin biopsy, integrating the practical experience of four internationally recognized dermatopathologists to address areas where evidence is limited or poorly standardized. The review covers biopsy planning, selection of the optimal biopsy site and technique, specimen handling and fixation, grossing and laboratory processing, prevention of technical artifacts, the use of ancillary diagnostic techniques, and clinicopathological correlation, with particular attention to challenging anatomical sites and complex diseases. Diagnostic accuracy depends on obtaining a representative specimen, maintaining high technical standards throughout tissue processing, providing adequate clinical information, and ensuring close communication between the clinician and the dermatopathologist. In selected cases, multidisciplinary review is required to reach a definitive diagnosis. Adherence to these principles can optimize diagnostic yield, reduce avoidable errors, and ultimately improve patient care.
