Background Erythema elevatum diutinum (EED) is a rare vasculitis with variable clinical presentation which diagnosis can be challenging. Herein we want to describe the clinicopathological spectrum of findings in five cases of EED. Methods We retrospectively analyzed five cases in a single institution collected over a period of 27 years. The clinical history was collected and all the slides were examined to determine the histopathological characteristics of the lesions. Results The mean age of our patients is 56.6 years. Two of five patients were females and with lesions showing predilection for the upper‐extremities. The most common presentation was of an erythematous plaque on the extensor surfaces. Three patients had a history of neoplasm. All cases showed leukocytoclastic damage consistent with EED. Conclusion Our findings suggest that EED shows a heterogeneous clinical and pathological presentation, which can show an overlap with granulomatous dermatoses and mixed connective tissue diseases. Scalp lesions can occur and can mimic granulomatous dermatoses. The finding of EED in benign and malignant solid tumors in three of our patients begs the question whether there is an association between EED and such solid neoplasms.

Background: Purpura fulminans, an uncommon syndrome of intravascular thrombosis with hemorrhagic infarction of the skin, is often accompanied by disseminated intravascular coagulation (DIC) and multi-organ failure, and may ultimately lead to death. Methods: Herein, we document 13 skin biopsies from 11 adult patients with the clinical diagnosis of sepsis and confirmed histopathologic diagnosis of intravascular thrombosis and/or DIC, compatible with acute infectious purpura fulminans (AIPF). Detailed history and clinical examination were performed, and the lesions were correlated with histopathologic findings. Any underlying medical disease was taken into consideration. Results: There were 5 males and 6 females with lower extremity or peri-incisional purpuric skin lesions. The most important comorbidities identified were a history of surgical procedure or neoplasm, although 4 patients had no relevant underlying history. Most skin biopsies revealed focal epidermal ischemia or necrosis and 3 showed full-thickness epidermal necrosis. In the underlying dermis, there were fibrin thrombi in superficial and deep blood vessels with acute inflammation. Changes of an inflammatory destructive vasculitis were identified in 5 cases. No bacteria or fungi were identified on histopathology. Conclusions: AIPF is a rapidly-progressing medical emergency which may be identified by histopathology in culture-negative cases. Biopsies may show neutrophilic infiltrate without infective organisms.

Mycobacterium abscessus and M. chelonae belong to the rapid‐growing nontuberculous mycobacteria (NTM) group, which are defined by their ability to form visible colonies on agar within 7 days of subculture. Cutaneous infections by this complex show a heterogeneous clinical presentation with varied histopathologic findings. However, the presence of vacuoles in many specimens has been reported as a specific histologic finding. Herein, we correlate the histopathology of patients with tissue‐culture positive M. abscessus/M. chelonae complex in order to identify features that may prompt a rapid categorization of the infectious etiology. The cohort includes 33 skin punch biopsy specimens from 28 patients who had associated positive tissue cultures. The most frequent clinical presentation was a single or multiple nodule. Twenty‐seven specimens (81.81%) were found to have vacuoles. The observation of certain histologic features (ie, polymorphonuclear microabscesses and epithelioid granuloma formation) should raise the possibility of infection by NTM. In addition to these findings, we believe the presence of vacuoles in the dermal and subcutaneous inflammation should raise suspicion for NTM.

Bacillary angiomatosis (BA) is an uncommon systemic disease caused by Bartonella henselae (BH) or Bartonella quintana (BQ) that occurs primarily in immunocompromised hosts. Few cases of BA recipients have been reported in adult solid transplant recipients over the years, with most cases presenting years after transplant. We describe a case of a kidney transplant recipient who developed cutaneous BA very early in the post-transplant period despite not having any exposures. Retrospective testing of donor and recipient's serum was performed and raised the concern for possible How to cite this article: Morillas JA, Hassanein M, Syed B, et al. Early post-transplant cutaneous bacillary angiomatosis in a kidney recipient: Case report and review of the literature.

Background: The role of the mammalian target of rapamycin (mTOR) in hair follicle tumorigenesis is unclear. mTOR controls cell growth and can be activated through ribosomal S6 kinase.Herein, we sought to evaluate the expression of phospho-S6 in six different benign and malignant follicular tumor types.Methods: 76 cases were selected (17 fibrofolliculomas, 20 trichoepitheliomas, 10 tricholemmomas, 19 pilomatricomas, 1 malignant proliferating tricholemmal tumor, 8 tricholemmal carcinomas, and 1 trichoblastic carcinoma) and collected over 16 years. Immunohistochemistry with monoclonal antibody for phospho-S6 was performed and analyzed semi-quantitatively; statistical analysis using the χ 2 test was performed, with P < 0.05 considered significant. Results: All malignant neoplasms in our series (8/8 [100%] cases of tricholemmal carcinoma, 1/1 [100%] trichoblastic carcinoma, and 1/1 [100%] malignant proliferating tricholemmal tumor)showed a strong and diffuse pattern of staining for phospho-S6 involving 70% to 90% of tumor cells. By contrast, a minority of benign tumors were positive for phospho-S6 and most stained in a patchy pattern including 12/17 (71%) fibrofolliculomas, 9/20 (45%) trichoepitheliomas and 1/10 (10%) tricholemmomas, involving 30% to 50%, 5% to 20%, and 40% to 50% of tumor cells, respectively. Most pilomatricomas (17/19 [89%]) exhibited a stronger, but distinctive staining pattern, staining mostly the basaloid cells with a multifocal distribution, involving 70% to 90% of tumor cells.Conclusions: Phospho-S6 is differentially expressed among benign and malignant hair follicle tumors (P = 0.0044). While malignant tumors show diffuse expression, only a small subset of benign neoplasms were positive, primarily in a patchy distribution. K E Y W O R D Shair follicle tumors, mTOR pathway, phospho-S6