Sebaceous gland atrophy due to seborrheic dermatitis in a patient with alopecia: A potential pitfall.

Seborrheic dermatitis is an inflammatory condition that usually presents with erythema, scaly greasy papules, and plaques affecting sebaceous gland-rich areas and predominantly involving the face and scalp. The diagnosis of seborrheic dermatitis can often be rendered based on the clinical presentation. However, in certain cases, a biopsy can be useful to distinguish it from clinical mimics such as psoriasis, discoid lupus, and rosacea. Prominent sebaceous gland atrophy without scarring has been well-described as an important and relatively specific clue for psoriatic or drug-induced alopecia. However, sebaceous gland atrophy is not specific to psoriasis and has been demonstrated in seborrheic dermatitis, facial discoid dermatitis, and potentially may occur in other inflammatory dermatoses of the scalp. We report a 23-year-old female patient presenting with non-scarring hair loss and histopathological findings demonstrating mild androgenetic alopecia and changes of seborrheic dermatitis with dramatic sebaceous gland atrophy. The patient had no history or evidence of psoriasis clinically. Our case suggests that in patients with seborrheic dermatitis, sebaceous gland atrophy may complicate the evaluation of alopecia biopsies and should be recognized as a pitfall. Seborrheic dermatitis should be included in the differential diagnosis of alopecia biopsies showing prominent sebaceous gland atrophy.

Dermal Granuloma Annulare After SARS-CoV-2 Vaccination: A Rare Complication.

Granuloma annulare (GA) is an inflammatory granulomatous skin disease of unknown etiology that is self-limiting in nature. However, it is hypothesized that trauma, medications, malignancy, viral infections, different vaccines, and hypersensitivity reactions can trigger the formation of GA. Only three cases of post-SARS-CoV-2 vaccination-related GA have been reported so far. Here, we report the fourth documented case of post-SARS-CoV-2 vaccination-related generalized GA.

Molecular Profiling of Syringocystadenocarcinoma Papilliferum Reveals RAS-Activating Mutations.

CONTEXT.­: Syringocystadenocarcinoma papilliferum (SCACP) is a rare adnexal carcinoma and the malignant counterpart of syringocystadenoma papilliferum (SCAP), which is commonly located on the head and neck and may arise in association with a nevus sebaceus. RAS mutations have been identified in both SCAP and nevus sebaceus. OBJECTIVE.­: To evaluate the clinicopathologic and molecular features of SCACPs, which have not been previously explored. DESIGN.­: We obtained 11 SCACPs from 6 institutions and reviewed the clinicopathologic features. We also performed molecular profiling using next-generation sequencing. RESULTS.­: The cohort comprised 6 women and 5 men with ages ranging from 29 to 96 years (mean, 73.6 years). The neoplasms occurred on the head and neck (n = 8; 73%) and extremities (n = 3; 27%). Three tumors possibly arose in a nevus sebaceus. A total of 4 cases showed at least carcinoma in situ (adenocarcinoma, n = 3; squamous cell carcinoma [SCC], n = 1), and 7 cases were invasive (SCC, n = 5; mixed adenocarcinoma + SCC, n = 2). A total of 8 of 11 cases (73%) had hot spot mutations consisting of HRAS (n = 4), KRAS (n = 1), BRAF (n = 1), TP53 (n = 4), ATM (n = 2), FLT3 (n = 1), CDKN2A (n = 1), and PTEN (n = 1). All 4 cases with HRAS mutations occurred on the head and neck, whereas the KRAS mutation occurred on the extremity. CONCLUSIONS.­: RAS-activating mutations were detected in 50% of the cases, of which most (80%) involved HRAS and occurred on the head and neck, which shows overlapping features with SCAP, supporting that a subset may arise as a result of malignant transformation and likely an early oncogenic event.

Bullous Tinea: Single-Center Retrospective Histopathologic Review of 25 Skin Biopsies.

CONTEXT.­: Bullous dermatophytosis is a rare blistering disorder resulting from fungal infection. Limited literature describes the clinical and microscopic features of this disease. OBJECTIVE.­: To summarize the histopathologic and clinical features of 25 biopsy-proven cases of bullous tinea. DESIGN.­: The study was a single-center retrospective review of patients diagnosed with bullous dermatophyte infection by skin biopsy. RESULTS.­: Bullous tinea is rarely suspected clinically in biopsy-proven cases, often mimicking other spongiotic disorders that can vesiculate. In addition to classically taught histopathologic clues, several unique characteristics were observed in our population. The presence of dermal neutrophils as the nonpredominant cell type (85%; n = 17 of 20) can serve as an additional clue to diagnosis. Deep inflammation (25%; n = 5 of 20) does not exclude a superficial diagnosis. The classically taught sandwich sign (32%; n = 8 of 25) may be less relevant in the setting of bullous tinea. Hyphae were most commonly seen within the stratum corneum adjacent to this blister rather than within the blister itself, and special staining was required in a substantial number of cases (40%; n = 10 of 25) to reach the correct diagnosis. CONCLUSIONS.­: Bullous tinea is unusual but should be considered in the differential diagnosis of blistering skin disorders. Hematoxylin and eosin-stained slides frequently lack obvious fungal hyphae; for this reason, periodic acid-Schiff reaction or Gomori/Grocott methenamine silver stains should be routinely considered for biopsies showing intraepidermal and/or subepidermal blister formation and prominent neutrophil infiltration to prevent misdiagnosis.

Bilateral eyelid swelling as the presenting sign of subcutaneous sarcoidosis.

An 18-year-old Black female presented with a 2-year history of bilateral upper eyelid swelling and the recent onset of multiple subcutaneous nodules on the arms. She had previously undergone evaluation and treatment for presumed angioedema. Biopsies of the eyelid and an arm nodule demonstrated non-necrotizing granulomatous inflammation with special stains negative for acid-fast bacilli and fungi, and the patient was diagnosed with subcutaneous sarcoidosis. The isolated finding of bilateral eyelid swelling 2 years prior to the onset of additional cutaneous findings led to a significant delay in diagnosis, highlighting the importance of considering sarcoidosis in the differential diagnosis for bilateral eyelid swelling.

HPV-associated Vulvar Intraepithelial Carcinoma With Sebaceous Differentiation: Report of 2 Cases.

Sebaceous carcinoma (SC) is a malignant neoplasm demonstrating sebocytic differentiation, commonly in the periocular area. Sebocytic differentiation is recognized by multivesicular cytoplasmic clearing with frequent nuclear scalloping. The vesicles can be highlighted by immunohistochemical stains against the perilipin family proteins including adipophilin. Extraocular SC is uncommon but well reported, often in the setting of Muir-Torre syndrome; however, vulvar SC is exceptionally rare. The literature review yielded only 12 prior cases of vulvar SC, all of which showed invasion. Here we report 2 additional similar cases from 2 different institutions of an intraepithelial carcinoma with sebaceous differentiation. Histologic examination of multiple specimens from both patients showed similar features: a multifocal intraepithelial basaloid nodular neoplasm sparing the basal layer with occasional pagetoid spread. The tumor cells demonstrated a high nuclear to cytoplasmic ratio, mitoses, variably foamy vacuolated cytoplasm, and nuclear indentation. Multiple specimens from both patients showed evidence of sebaceous differentiation (substantiated by adipophilin positivity in a membranous vesicular pattern in case 1 and by androgen receptor and epithelial membrane antigen positivity in case 2), and squamous differentiation (substantiated by p63/p40 and weak CK 5/6 expression), as well as human papillomavirus (HPV) association (substantiated by p16 block positivity and detection of high-risk HPV by in situ hybridization). One case was a true in situ lesion without evidence of invasion, and the other case was predominantly an in situ carcinoma with prominent adnexal extension and focal superficial invasion of <1 mm seen in one of multiple specimens. To our knowledge, these 2 cases are the first to show a vulvar SC/carcinoma with sebaceous differentiation that is predominantly limited to the epidermis, and the first documentation of HPV infection in vulvar sebaceous neoplasms. Vulvar intraepithelial carcinoma with sebaceous differentiation is the umbrella term we chose for this entity. Whether this is a true SC in situ that is HPV positive/driven, or a vulvar intraepithelial neoplasia with sebaceous differentiation, is not entirely clear. We emphasize the importance of looking for this morphology to avoid misclassification. Due to the rarity of cases, optimal treatment at this site has not been established.

Demographics and perceptions of diversity in dermatopathology workforce and training environments in the United States.

OBJECTIVES: The aim of this study was to determine the demographics and perceptions of diversity, equity, and inclusion (DEI) in the field of dermatopathology to provide a measurable baseline for future efforts to enhance equity measures within our subspecialty. METHODS: A questionnaire based on a previously validated instrument by Association of American Medical Colleges (AAMC) was sent to American Society of Dermatopathology (ASDP) members to collect the demographic information (gender, race, sexual orientation, disability, experience and practice setting, etc.) and evaluate eight diversity, engagement, and inclusivity statements on a 1-5 Likert scale. RESULTS: The demographics of 207 of 1331 (15%) respondents showed slight male predominance. Eleven percent of respondents identified as LGBTQI. The major racial distribution was comprised of 62% White, 18% Asian (including Middle Eastern/Indian), 10% Hispanic, and 4% Black respondents. New-in-practice respondents (those in practice-5 years or less) were more likely to have a pathology background (71% vs. 56%, p = 0.047) than their more-established peers with more than 5 years of service. This trend also contributed to increased diversity in terms of gender (66% females) and race (48% non-White) among the newer generation. Dermatology-trained dermatopathologists were mostly White (70%) and male (53%). Analysis of respondent demographics with perception statements showed that White and US graduate respondents (compared to other groups) were more likely to have a positive perception about DEI within the field of dermatopathology. CONCLUSIONS: The results provide a snapshot of the current state of diversity within the field of dermatopathology. Moreover, these results highlight opportunities for further increasing diversity in general and leadership in particular within dermatopathology.

Cutaneous T-Cell Lymphoma (CTCL) Arising Post Kidney Transplant: A Review of Clinical Variants in the Literature.

Post-transplant lymphoproliferative disease is a rare disorder with an annual incidence of 0.5% to 3.7%. Development of this disorder carries with it a poor prognosis. In this report, we describe a rare case of post-transplant primary cutaneous T-cell lymphoma (PT-CTCL) mycosis fungoides stage IIB in a patient following kidney transplantation, as well as a review of PT-CTCL reported in the literature. The treatment following diagnosis included bexarotene, cyclosporine, and prednisone. Currently, the patient is free from disease. This information aims to add to the knowledge of the prevalence and management of PT-CTCL.

Cutaneous Oxalosis Due to Primary Hyperoxaluria.

ABSTRACT: A 19-year-old girl presented to the emergency department with a progressively painful purpuric lesion on the left dorsal foot, which had initially appeared 2 days prior. Three months earlier, she had been diagnosed with end-stage renal disease. Her medical history also included recurrent urolithiasis for the past 5 years and liver failure. Biopsy revealed oxalate crystals occluding vessels with secondary epidermal and dermal ischemia. Oxalate crystals were also visualized in the vessel walls and free in the subcutis. Genetic testing confirmed the diagnosis of primary hyperoxaluria type 1. She was treated with sodium thiosulfate, apixaban, pentoxifylline, wound care, and palliative care. At 4-month follow-up, the cutaneous manifestations of oxalosis were confined to only her feet, and she was undergoing evaluation for combined liver and kidney transplant. Cutaneous oxalosis because of primary hyperoxaluria should be considered in young patients presenting with purpuric lesions, recurrent urolithiasis, and early-onset renal failure.

Milia en plaque manifesting as a post-herpetic isotopic response.

Isotopic response in dermatology refers to the development of a new primary dermatosis at the site of a previous reaction such as cutaneous herpes virus infection. We report a 63-year-old woman with a recent history of a bullous drug eruption treated with prednisone who presented with herpetic dermatitis and subsequent milia en plaque. This unique case represents a novel presentation of milia en plaque manifesting as a complication from post-herpetic isotopic response and highlights the wide array of isotopic responses that can occur following a cutaneous herpes simplex infection.

Primary Cutaneous Alveolar Rhabdomyosarcoma in an Elderly Adult: A Rare Potential Mimic of Merkel Cell Carcinoma.

ABSTRACT: Rhabdomyosarcoma (RMS) rarely arises as a primary skin tumor. It is also very rare in older adults, especially the alveolar type. We report an 80-year-old White woman who presented with a painful, erythematous, raised lesion (2 × 3.5 cm) above the left knee that was fixed within the skin, yet mobile about underlying soft tissue. A punch biopsy showed monotonous malignant round blue cells involving the dermis. Immunostains showed diffuse expression of CD56, focal chromogranin, focal dot-like pancytokeratin, CK7, and neurofilament, but negative for synaptophysin, CK20, SOX-10, MUM-1, CD43, TTF-1, and CD99. A CK20-negative variant of Merkel cell carcinoma was initially favored, but given the unusual immunophenotype and the presence of cellular dyscohesion, desmin and myogenin stains were performed, both of which were diffusely positive. Molecular testing revealed rearrangement of PAX3 and FOXO1 loci, confirming the diagnosis of alveolar RMS. PET/CT showed a probable 1.9-cm left inguinal lymph node metastasis; no internal or deep soft tissue primary tumor mass was identified, supporting a true primary cutaneous origin. Alveolar RMS may express keratins and neuroendocrine markers, making it easy to confuse with Merkel cell carcinoma on those exceptionally rare instances, when it arises in the skin of older adults.

Dermatofibrosarcoma protuberans with platelet-derived growth factor-D rearrangement; two cases with morphologically distinct presentations.

Dermatofibrosarcoma protuberans (DFSP) is a mesenchymal neoplasm that is usually located in the dermis or subcutis and is locally aggressive. Rarely, these lesions may undergo fibrosarcomatous transformation, which is thought to increase their metastatic potential. DFSP is classically associated with a 17;22 translocation (or ring chromosome thereof) resulting in fusion of the COL1A1 and PDGFB genes. However, variant fusions involving PDGFD have been recently reported. Herein, we present two morphologically diverse cases of DFSP with PDGFD rearrangement. Case 1 is a 68-year-old female with a left dorsal foot lesion. Morphologically, the lesion is unusual as it is a well-circumscribed, hypercellular, subcutaneous nodule with uniform CD34-positive spindle cells arranged in a herringbone pattern without storiform arrangement or "honeycombing" fat entrapment. It was diagnosed as pure fibrosarcomatous DFSP. Case 2 is a 37-year-old male with a right supra-auricular lesion. Morphologically, the lesion displays classic DFSP features including bland CD34-positive spindle cells with storiform growth, fat entrapment, and infiltrative borders. Both lesions were negative for COL1A1-PDGFB fusion but positive for PDGFD rearrangement by fluorescence in situ hybridization (FISH) analysis. FISH testing for PDGFD rearrangement should be performed in cases where there is a high suspicion for DFSP but initial studies for COL1A1-PDGFB are negative.

Blue nevus with smooth muscle hyperplasia: A rare hamartoma.

A limited number of distinct histopathological variants of blue nevus exist, and hamartomatous proliferations involving melanocytic components, dendritic, or otherwise, have also been described. Blue nevus/smooth muscle hamartomas represent a rarely described entity. In this paper, we add two examples of this unusual hamartoma to the existing literature. These additional blue nevus/smooth muscle hamartomas occurred on the left mid-upper back of a 50-year-old woman and the central upper back of a 54-year-old man. Both lesions were clinically atypical pigmented lesions. Histopathologic review of both specimens revealed proliferations of predominantly spindled and pigmented dermal melanocytes with associated smooth muscle hyperplasia, compatible with blue nevus/smooth muscle hamartoma. Both specimens were accompanied by subtle changes suggesting follicular induction, a phenomenon previously described as occurring in a minority of specimens. A brief re-examination of recently diagnosed blue nevus at our institution did not reveal any additional cases in which a subtle smooth muscle component had been missed, suggesting this type of hamartoma is, indeed, exceedingly rare.

Appropriate use criteria for ancillary diagnostic testing in dermatopathology: New recommendations for 11 tests and 220 clinical scenarios from the American Society of Dermatopathology Appropriate Use Criteria Committee.

BACKGROUND: Appropriate use criteria (AUC) provide patient-centered physician guidance in test selection. An initial set of AUC was reported by the American Society of Dermatopathology (ASDP) in 2018. AUC reflect evidence collected at single timepoints and may be affected by evolving evidence and experience. The objective of this study was to update and expand AUC for selected tests. METHODS: RAND/UCLA (RAND Corporation [Santa Monica, CA]/University of California Los Angeles) methodology used includes the following: (a) literature review; (b) review of previously rated tests and previously employed clinical scenarios; (c) selection of previously rated tests for new ratings; (d) development of new clinical scenarios; (e) selection of additional tests; (f) three rating rounds with feedback and group discussion after rounds 1 and 2. RESULTS: For 220 clinical scenarios comprising lymphoproliferative (light chain clonality), melanocytic (comparative genomic hybridization, fluorescence in situ hybridization, reverse transcription polymerase chain reaction, telomerase reverse transcriptase promoter), vascular disorders (MYC), and inflammatory dermatoses (periodic acid-Schiff, Gömöri methenamine silver), consensus by panel raters was reached in 172 of 220 (78%) scenarios, with 103 of 148 (70%) rated "usually appropriate" or "rarely appropriate" and 45 of 148 (30%), "appropriateness uncertain." LIMITATIONS: The study design only measures appropriateness. Cost, availability, test comparison, and additional clinical considerations are not measured. The possibility that the findings of this study may be influenced by the inherent biases of the dermatopathologists involved in the study cannot be excluded. CONCLUSIONS: AUC are reported for selected diagnostic tests in clinical scenarios that occur in dermatopathology practice. Adhering to AUC may reduce inappropriate test utilization and improve healthcare delivery.

Characterization of Morphologic and Cytochemical Staining Properties of Exogenous Materials Mimicking Fungal Organisms Encountered in Skin Biopsies.

BACKGROUND: Exogenous materials may be encountered in skin biopsies as contamination. Contamination may occur during the biopsy procedure in the clinic or during tissue processing in the laboratory. Although the experienced pathologist may often instinctively ignore clear examples of contamination, such tissue may be a source of confusion for young pathologists and those in training. Foreign materials can typically be recognized as exogenous by morphology, polarizability, and the presence or absence of a tissue reaction, but we have rarely encountered situations in which exogenous materials could be misinterpreted as organisms, either by their morphologic appearance or staining properties. METHODS: Exogenous materials used during skin biopsy and grossing were embedded in a nonhuman tissue scaffold and prepared into histologic slides. Hematoxylin and eosin (H&E), periodic acid-Schiff with diastase, and Grocott methenamine silver stains were performed, and each material was evaluated under polarized microscopy. RESULTS: Exogenous materials were divided into the following 3 categories with shared morphologic appearances and staining properties: suture materials, plant-based materials, and synthetic materials. CONCLUSION: We present a comprehensive characterization of the morphologic and cytochemical staining properties of multiple exogenous materials that may contaminate a skin biopsy. This characterization will aid the pathologist by providing a mechanism to identify potential contaminants in skin biopsies.

Deep Herpes.

Herpes viruses are known for infecting epithelial cells and manifesting as vesicles. However, herpes viruses can also infect stromal cells. While established in the ocular setting, cutaneous stromal herpes (deep herpes) is previously unreported and may evade clinical and microscopic detection. We searched for skin biopsies with herpes stromal disease. Clinical information was retrieved via electronic medical records and pathology records system. Hematoxylin and eosin slides, immunohistochemical staining, and polymerase chain reaction detection of viral DNA was performed. We identified 12 specimens from 10 patients with cutaneous stromal herpes simplex virus 1/2 (n=7) or varicella-zoster virus infection (n=5). The most common site involved was the buttocks/perianal region (n=6). Ulceration was a frequent dermatologic finding (n=8). Pyoderma gangrenosum was clinically suspected in 6 specimens (50%). Eight patients (80%) were immunosuppressed. Biopsies frequently demonstrated a dense dermal mixed inflammatory infiltrate with subcutaneous extension and enlarged cells with viral cytopathic changes confirmed by herpes simplex virus 1/2 or varicella-zoster virus immunohistochemistry (n=10) or polymerase chain reaction (n=2). Most specimens (67%) lacked evidence of characteristic epidermal keratinocyte infection. This study presents the first known report of the ability of herpes virus to infect deep stromal cells of the dermis. We raise awareness of cutaneous stromal herpes in patients presenting with atypical clinical lesions, particularly while immunocompromised. Establishing the correct diagnosis is critical for initiating therapy.