Case Report: Dermoscopic and pathologic features of primary cutaneous follicle center lymphoma involving the nasal ala.

Background: Primary cutaneous follicle center lymphoma (PCFCL) is a rare, indolent B-cell lymphoma that typically presents as asymptomatic lesions on the scalp, forehead, or trunk, with disease confined to the skin. Involvement of the nasal region is highly uncommon and prone to misdiagnosis because of its nonspecific clinical features. Case description: An 84-year-old woman presented with a collection of asymptomatic, firm, agminated papules on the left nasal ala, first noted about 2 years prior. At dermoscopy, the lesions presented fine, linear, irregular vessels on a salmon-colored background. The histopathological evaluation revealed nodular lymphoid infiltrates within the dermis, a prominent grenz zone, and well-demarcated lymphoid follicles composed of atypical lymphocytes with a thin mantle zone. The immunohistochemical analysis showed diffuse positivity for CD20, BCL6 and CD10, and negativity for BCL2 and CD5 in the atypical cells, which were surrounded by a thin layer of CD3-positive reactive T lymphocytes. The diagnosis of PCFCL was established on the basis of the clinical, dermoscopic, and histopathologic findings, and curative radiation therapy was initiated. Conclusion: PCFCL involving the nasal ala is extremely rare and presents with nonspecific dermoscopic patterns that may delay or obscure diagnosis. Accurate identification relies on the integration of dermoscopic assessment, histopathological examination, and immunohistochemical profiling.