Journal of Cutaneous Pathology最新文献

Leprosy shows a broad spectrum of clinical and histopathological features depending on host immunity and disease stage. The characteristic “leprosy pattern” involves superficial and deep dermal infiltrates in perivascular, peri-appendageal, and perineural locations. While tuberculoid leprosy and cutaneous sarcoidosis may occasionally have overlapping histopathology, borderline lepromatous (BL) leprosy demonstrating sarcoidal granulomas is uncommon. We report a 50-year-old female presenting with multiple infiltrated erythematous and hypoesthetic plaques, and asymmetrically thickened peripheral nerves. Skin biopsy from a clinically downgraded lesion revealed sarcoidal granulomas (discrete, non-caseating, with sparse lymphocytic rims); however, the presence of interspersed foamy histiocytes, a distinct Grenz zone, and acid-fast bacilli on Wade-Fite stain, together with clinicopathologic correlation, confirmed a diagnosis of BL leprosy. Ancillary investigations helped rule out sarcoidosis. This case presents the diagnostic challenge created by overlapping granulomatous patterns, and reinforces the importance of detailed clinicopathologic correlation and ancillary testing including mycobacterial stains, especially since slit-skin smears are often negative in borderline cases. Recent studies have shown that changes in immune cell composition within granulomas can influence transition along the leprosy spectrum and may possibly give rise to atypical morphologies (like sarcoidal patterns). Early diagnosis and treatment remain central to leprosy control, and awareness of such presentations can help avoid diagnostic delay in endemic regions.

Wnt/β-catenin-activated nonpilomatrical rosette-forming carcinoma is a recently described skin neoplasm with a distinct morphology and pathogenic profile involving mutations in the APC/CTNNB1 and RB1 genes. We report a Wnt/β-catenin-activated, invasive, rosette-forming carcinoma surrounded by Bowen disease on the leg of a 90-year-old woman. Pathogenic mutations in RB1 and APC with allelic frequencies of 83.5% and 53.92%, respectively, were detected by NGS. The invasive tumor showed a predominantly peripheral basaloid component forming rosettes and a poorly differentiated squamoid component and exclusively the former arose multifocally in the Bowen disease. Heterogeneous synaptophysin, chromogranin, BerEp4, and CK7 immunostaining were present in the invasive tumor but not in Bowen disease. Diffuse nuclear β-catenin and Rb loss were found in both invasive components. In Bowen disease, there was also diffuse Rb loss but only some variably sized spots of nuclear β-catenin immunostaining. CDX2 immunoreactivity varied among the three components. It was more extensive in poorly differentiated areas and showed an inverse correlation with the proliferation rate. Our histopathologic, immunohistochemical and genetic findings provide further evidence that Bowen disease may act as a precursor for the rosette-forming component of the Wnt/β-catenin-activated carcinoma and that there is an inverse correlation between CDX2 expression and the proliferation rate.

Ectomesenchymal chondromyxoid tumor (EMCMT) is a rare benign neoplasm of uncertain histogenesis that typically involves the anterior portion of the tongue. Approximately 114 cases have been documented in the literature, with 9.6% reported from South America. Herein, we describe a case of EMCMT and discuss its clinicopathological features, differential diagnosis, and treatment. A 25-year-old woman presented with an 11-year history of an asymptomatic nodular lesion on the left lateral-middle dorsal surface of the tongue. Surgical excision was performed. Histopathological examination revealed a multilobulated myxoid tumor composed of spindle-shaped and polygonal cells. Immunohistochemical analysis showed diffuse positivity for glial fibrillary acidic protein and S-100 protein. No recurrence was observed after 12 months of follow-up. This case highlights the prototypical clinicopathological features of EMCMT and underscores the importance of its recognition in the differential diagnosis of tongue nodules. To the best of our knowledge, this represents the first documented case from Venezuela, contributing to the geographic expansion of EMCMT data and emphasizing the need for clinical awareness, particularly in resource-limited settings.