Indolent systemic mastocytosis (ISM) is a group of heterogenous diseases characterized by abnormal accumulation of mast cells in at least one organ. ISM can be a cause of osteoporosis. The aim of this study is to determine the prevalence, and the prognosis of ISM in a cohort of patients with osteoporosis. In this monocentric and retrospective study, patients with osteoporosis who did not receive a bone biopsy (cohort 1) and patients that subsequently received a diagnostic bone biopsy for differential diagnosis (cohort 2) are compared with patients who are diagnosed with ISM (cohort 3). A total of 8392 patients are diagnosed with osteoporosis. Out of these patients 1374 underwent a diagnostic bone biopsy resulting in 43 patients with ISM. These figures indicate that ISM is diagnosed in 0.5% of patients with osteoporosis and in 3.1% (men 5.8%) of patients who underwent bone biopsies. Patients with ISM sustained significantly more vertebral fractures in comparison to patients in cohort 2 (4.4 ± 3.6 versus 2.4 ± 2.5 vertebral fractures, p < 0.001) and women were significantly younger compared to cohort 2 (57.3 ± 12 versus 63.6 ± 12 years, p < 0.05). Only 33% showed an involvement of the skin (urticaria pigmentosa). ISM is a rare cause of osteoporosis (0.5%). However, in a subgroup of rather young male patients with osteoporosis the prevalence is more than 5%. Thus, ISM should be considered in premenopausal women and men presenting with vertebral fractures even if urticaria pigmentosa is not present.

Pregnancy and lactation-associated osteoporosis (PLO) is a very rare form of osteoporosis. Vertebral fractures either occur in the last trimester of pregnancy or after childbirth. Pathogenesis is still unclear. Until recently, almost no data existed in regards to the quality of life and long-term clinical outcome of patients with PLO. To determine the long-term clinical outcome of patients with pregnancy and lactation-associated osteoporosis (PLO) with respect to the following factors: pain, quality of life, mental condition, vertebral fractures, and capacity to work. In this single-center retrospective study, patients were reviewed for at least 2 years, more than 50% of them were followed up until menopause. Bone density (DXA) and vertebral fractures were assessed. Standardized questionnaires were used to analyze factors such as quality of life (Qualeffo-41), anxiety and depression (PHQ-4), and pain (the visual analog scale [VAS]). Additionally, a questionnaire was designed in order to evaluate and discuss some of the reasons behind the occurrence of mental distress at the onset of symptoms. Our report shows the clinical course of 20 patients with PLO, 11 of them until menopause (on average 16.3 years after onset of symptoms). When diagnosis was made, 5.4 vertebral fractures were noticed on average. Three of the 20 patients developed subsequent fractures in the following years. The diagnosis of PLO was made on average after 3.3 months after the onset of symptoms. At the beginning of the investigation, physical and mental health of all patients were poor, but improved within the first 2 years and continued doing so until menopause. The average time it took to return to employment was 3.3 years. PLO has a significant impact on pain, mental state, quality of life, and capacity to work. However, the long-term prognosis is promising. The severe mental distress is presumably related to several contributing factors in life such as physical integrity and independence, family life, employment, and financial security.