American Journal of Dermatopathology

No abstract text is available yet for this article.

Syphilis is a sexually transmitted disease that can present a wide variety of clinical and histopathological manifestations. We present the case of a 75-year-old patient with a persistent maculopapular rash on the trunk and extremities, in which the biopsy showed an exclusively perifollicular granulomatous infiltrate. In the immunohistochemical staining with anti-Treponema pallidum antibodies, spirochetes scattered within the perifollicular inflammatory infiltrate were identified. These findings together with the serological analysis allowed the diagnosis of secondary syphilis...

Primary cutaneous spindle B-cell lymphoma is an uncommon subtype of cutaneous lymphoma characterized by a distinct spindled cytology of neoplastic B cells. Despite sharing clinical, histopathological, and phenotypical similarities with primary cutaneous follicle center lymphoma, an indolent form of B-cell lymphoma, it also exhibits certain features akin to primary cutaneous diffuse large B-cell lymphoma. Notably, in rare instances, a more aggressive clinical course has been observed. This report details a rare case of primary cutaneous spindle cell B-cell follicle center lymphoma, manifested as a prolonged solitary plaque of cicatricial alopecia...

This article reports two cases of the 2022 mpox virus with notable histopathology, and includes a novel description of mpox pseudotumor in the perianal region which is not previously described. This article additionally includes literature review of characteristic histopathology through evolving lesions, as it is sparsely described in relation to the 2022 mpox outbreak. Case one describes a 42-year-old man who presented with umbilicated, smooth papules on the trunk and extremities, and milia-like papules on the face...

Clinical correlation is essential to accurate and efficient diagnosis and differential diagnosis in dermatopathology. Poor-quality clinical information can lead to failures and delays in patient care. Some clinicians use the term "unlikely" when submitting a specimen. How frequently the "unlikely" clinical diagnosis correlates with the final pathologic diagnosis is unknown. We studied 203 dermatopathology reports from December 8, 2020, to July 1, 2021, that included the qualifier "unlikely" on the requisition sheet...

The conventional morphological characteristics of Wnt-activated deep penetrating/plexiform melanocytomas/nevi (DPN) are those of large spindled or epithelioid melanocytes with distinctive voluminous amphophilic cytoplasm, fine pigmented granules, and surrounding melanophages. The central molecular hallmark is the activation of the Wnt-pathway predominantly driven by mutations in the beta-catenin (CTNNB1) gene. Although typically lacking a junctional component, a lesser-known superficial variant with a junctional component has been identified, which could potentially lead to diagnostic challenges...

Nail involvement in Langerhans cell histiocytosis is rarely reported in the literature. According to the reported cases, it is believed that the involvement of nails has a poor prognosis because of multisystem involvement. Performing a nail bed biopsy might be challenging for children. We report a child in whom nail bed biopsy served as the sole clue to the diagnosis of Langerhans cell histiocytosis in absentia of skin clue on a background of advanced multisystem involvement.

Anetoderma is an uncommonly reported dermatosis clinically characterized by discrete skin lesions resulting from elastic fiber loss within the dermis. Although primary anetoderma has been considered idiopathic, a range of associated disorders, particularly prothrombotic abnormalities, have been reported. We present a 79-year-old woman with a heterozygous Factor V Leiden mutation who developed anetoderma shortly after COVID-19 infection complicated by a thromboembolic event. Our patient adds to the literature on the occurrence of anetoderma in the setting of infection and/or a prothrombotic disorder...

Plasmacytoid dendritic cell neoplasms are rare neoplasms originating from plasmacytoid dendritic cells (pDCs). They are subclassified into 2 types: blastic plasmacytoid dendritic cell neoplasm and mature plasmacytoid dendritic cell proliferation. Neoplastic expansion of pDCs has also been found to be associated with myeloid neoplasia. We present the diagnostically challenging case of a 62-year-old woman who presented to the emergency department with numerous hemorrhagic nodules and papules on the face and extensor surfaces near the elbows and neutropenic fevers...

BACKGROUND: Following transition to digital pathology for primary diagnosis at our institution, dermatology residents have reduced exposure to light microscopy. This study compares resident competency with light microscopy versus digital pathology following practice changes. METHODS: Twenty-one dermatology residents were administered a dermatopathology examination composed of 32 diagnoses evaluated using digital slides and 32 with light microscopy. Case difficulty was graded and balanced between modalities...

Mpox, previously referred to as monkeypox, was recently deemed a public health emergency in 2022. Our understanding of potential secondary cutaneous manifestations in the setting of this infection is still evolving. We report a rare case of a man who presented with erythematous, painful subcutaneous nodules on his extremities in the setting of recent mpox infection. Biopsy of a lesion from the lower legs revealed a lobular panniculitis with lupus panniculitis-like features on pathology. He was ultimately diagnosed with a unique case of reactive panniculitis secondary to mpox...

No abstract text is available yet for this article.

Refractory celiac disease (RCD) is a rare condition characterized by persistent malabsorptive symptoms and villous atrophy despite a gluten-free diet. While RCD type 1 has a normal intraepithelial lymphocyte phenotype, RCD type 2 is defined by the presence of immunophenotypically aberrant and monoclonal intraepithelial T lymphocytes, with a high propensity to transform to enteropathy-associated T-cell lymphoma (EATL). Although dermatological manifestations of celiac disease are common, presentation with cutaneous involvement by abnormal lymphocytes of RCD type 2 or EATL is rare, with few histologic descriptions in the literature...

Paratesticular mesothelioma (malignant mesothelioma arising from the tunica vaginalis of the testis) represents a small proportion of mesothelial neoplasms, and cutaneous involvement by paratesticular mesothelioma is very rare. Cutaneous involvement can manifest as scrotal subcutaneous nodules from regional spread, distant metastasis, or direct extension through surgical scars. Mesothelioma has 3 histopathologic classifications that include epithelioid, biphasic, and sarcomatoid, which is rarely seen in paratesticular mesothelioma...

A 45-year-old woman with a history of previously treated left plantar foot melanoma presented with a left thigh mass. Fine needle aspiration findings were concerning for metastatic melanoma (MM). Imaging was remarkable for PET-avidity of both the biopsied thigh mass and of a left posterior knee nodule. The knee nodule was also enhancing on MRI, concerning for a site of metastasis. Resection of the thigh mass and intra-articular nodule was performed. The thigh lesion was positive for MM. The specimen obtained from the knee demonstrated a proliferation of spindle and epithelioid cells associated with focal fibrosis and scattered giant cells with brown pigment, raising the possibility of melanoma metastasis with treatment effect...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

Interdigitating dendritic cell sarcoma is a rare, aggressive hematological malignancy primarily originating in lymph nodes, with only 10 reported cases presenting in the skin (primary cutaneous interdigitating dendritic cell sarcoma). Past presentations showed erythematous nodules on the proximal extremities, back, or face. Morphologically, these neoplasms are similar to melanomas and other dendritic cell (DC) tumors, making their diagnosis difficult. Here, we present 1 case of primary cutaneous interdigitating dendritic cell sarcomas and another 1 of malignant indeterminate dendritic cell tumor (indeterminate DC sarcoma)...

Cutaneous deciduosis is an extremely rare condition that clinically presents as a nodular lesion in the skin as a scar or neoplasm. Histologically, this may pose a diagnostic challenge simulating malignant epithelioid neoplasms including sarcoma. Histologically, a nodular growth pattern of large monomorphic epithelioid cells is observed. The epithelioid cells in deciduosis can appear atypical with considerable nuclear pleomorphism, mimicking a malignancy. These features can be misinterpreted as a primary cutaneous or metastatic malignancy by dermatopathologists who are not familiar with gynecologic pathology...

We report the case of a 72-year-old man with bilateral testicular involvement by mycosis fungoides (MF). The patient was diagnosed with MF 6 months prior, and testicular involvement was found upon staging. The rare behavior of MF, with early visceral involvement and no hematolymphoid organs affected, had a poor prognosis with patient death 14 months after the original diagnosis despite surgery and chemotherapy. The neoplastic cells showed a phenotypic switch from a CD4+/CD8- profile in the skin to a CD4-/CD8- in the testis and the same clone, confirmed with T-cell receptor gene rearrangement studies, making this the third reported case of MF affecting the testis and the first with clonality studies to confirm it...