Journal of Cutaneous Pathology最新文献

Cutaneous leishmaniasis presents with variable clinical and histopathological features, often complicating diagnosis. Acute lesions with high parasite burden are typically easier to identify, but chronic lesions with low organism load can be more challenging, particularly when leishmaniasis is not clinically suspected. Although granulomatous and lymphoplasmacytic infiltrates are well documented, our study underscores the diagnostic relevance of a plasma cell-rich, loosely organized granulomatous pattern. Observed in both Old and New World infections, this pattern may serve as a key histologic clue when organisms are sparse and confirmatory testing is limited or delayed. Recognizing it can prompt appropriate ancillary testing, guide treatment decisions, and reduce diagnostic delays, especially in low parasite burden cases or in settings where leishmaniasis is not routinely considered.

Primary cutaneous aggressive epidermotropic CD8⁺ cytotoxic T-cell lymphoma (PCAECTCL) is a rare, rapidly progressive cutaneous T-cell lymphoma that poses significant diagnostic challenges, particularly in mucocutaneous variants. We report a case in a 49-year-old man who presented with upper lip swelling initially misdiagnosed as angioedema and cheilitis granulomatosa. A lip biopsy revealed atypical CD4/CD8 double-negative T cells with marked epidermotropism, initially interpreted as pagetoid mycosis fungoides. Subsequent immunophenotyping demonstrated a cytotoxic profile (CD3⁺, CD2⁺, CD7⁺, CD5⁻, CD4⁻, CD8⁺, CD20⁺, perforin⁺, granzyme B⁺, TCRBF1⁺, CD56⁻, and TCRδ⁻). Imaging later identified tongue involvement with a similar phenotype, though CD8 expression was weak and CD20 expression was absent. The disease progressed to lymph nodes, oropharynx, and stomach, with an eventual phenotypic switch to CD8⁺. Molecular testing confirmed similar clonal T-cell rearrangements across all sites. Sequencing identified JAK3 and TP53 mutations, while chromosomal microarray revealed recurrent losses (1p, 2q, 3p, 4p, 11q, 13q, and 17q) and gains (7q, 17p), without JAK2 fusion. Despite aggressive therapy, the patient died 21 months after diagnosis. This case delineates the importance of early biopsy, integration of molecular studies, and the urgent need for therapies to improve outcomes in this aggressive lymphoma.

Leukemia cutis (LC) is a rare extramedullary manifestation of leukemia, most commonly associated with acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). The classic clinical presentation of LC usually includes various cutaneous lesions such as papules, nodules, and plaques. There are limited case reports describing a primary presentation with hyperpigmented macules and patches. This case report describes a 29-year-old male, diagnosed with AML, who initially presented with extremity skin dyspigmentation, unexplained lymphadenopathy, and fatigue. A skin biopsy revealed a dense periadnexal and perivascular infiltrate of atypical blastoid cells. Special stains for melanin (Fontana Masson) and iron were negative for abnormal deposition. Immunohistochemical stains showed scattered immature leukocytes (myeloperoxidase-positive), CD4-positive cells consistent with flow cytometry, and weak CD56 staining of admixed cells within the dense infiltrates. The patient was diagnosed with AML with an 11q23 KMT2A::AFF1 gene rearrangement—a mutation increasingly associated with a poor prognosis. This case underscores the importance of recognizing hyperpigmentation as a rare but potential manifestation of LC, especially in younger patients, and highlights the need for prompt diagnosis and intervention to improve patient outcomes.

Follicular Becker's nevus (FBN) is a rare variant of Becker's nevus defined by perifollicular pigmentation and folliculocentric distribution. We report two new cases in Caucasian women, aged 22 and 37, with lesions on the breast and lumbar regions. Both presented progressive, asymptomatic hyperpigmented macules since adolescence. Dermoscopy revealed donut-shaped perifollicular structures with hypopigmented halos surrounded by a reticulated brown network, while histopathology confirmed orthohyperkeratosis, basal pigmentation, elongated rete ridges, and hypertrophic arrector pili muscle bundles. In addition, we reviewed all published FBN cases, highlighting its distinct folliculocentric pattern, predilection for non-scapular sites, and occurrence beyond Asian cohorts. Both of our patients showed favorable outcomes with picosecond laser therapy, suggesting this approach as a promising treatment option.

Primary penile sarcomas are rare malignancies, accounting for less than 5% of penile cancers, with epithelioid angiosarcoma representing an exceptionally uncommon and aggressive subtype, documented in only about 30 cases worldwide. We report the case of a 59-year-old man who presented with an ulcerative lesion of the balanopreputial sulcus, initially presumed to be infectious or traumatic. Histopathological assessment following surgical excision revealed a poorly differentiated neoplasm initially suggestive of carcinoma. However, further expert pathological review and an extensive immunohistochemical panel identified a vascular neoplasm, with tumor cells expressing ERG, Fli-1, c-MYC, and focal CD31, alongside aberrant synaptophysin expression. The neoplasm lacked cytokeratins, additional neuroendocrine markers, and markers of melanocytic or myogenic differentiation. Molecular studies excluded hallmark translocations of other vascular or perivascular tumors but confirmed MYC gene amplification, supporting a definitive diagnosis of high-grade epithelioid angiosarcoma. This case highlights the diagnostic complexity of rare penile tumors and emphasizes the critical role of integrated histopathological, immunophenotypic, and molecular analyses in distinguishing aggressive vascular malignancies from their mimics.