Marginal zone lymphoma masquerading as phymatous acne rosacea: a case study.

Marginal zone lymphoma (MZL) is an indolent B-cell lymphoma characterized by considerable heterogeneity in clinical presentation. Cutaneous MZL typically manifests as papules, plaques or nodules, often affecting the trunk and arms. Rare cases of MZL presenting as acne rosacea have been reported; however, these have been primarily reported as granulomatous rosacea. Specific evidence of MZL presenting as phymatous acne rosacea is extremely rare and not well documented in the medical literature. We report a rare case of primary systemic nodal MZL manifesting alongside cutaneous extra-nodal MZL, mimicking rhinophymatous and otophymatous acne rosacea. An 84-year-old White man with a 13-year history of nodal MZL, under active monitoring, presented with erythematous, swollen lesions on the ears and nose. This was initially diagnosed as acne rosacea; however, conventional treatment proved ineffective, and the patient was referred for dermatological evaluation. A skin biopsy from the earlobe revealed a diffuse infiltrate of small lymphoid B cells, positive for CD20, CD79a and BCL2, and negative for CD5 and CD23, consistent with cutaneous MZL. Further imaging revealed systemic involvement, with enlarged lymph nodes above and below the diaphragm and splenomegaly. The patient was started on R-CVP chemotherapy (rituximab, cyclophosphamide, vincristine and prednisolone), leading to significant improvement in both the skin lesions and systemic disease. However, due to chemotherapy intolerance, treatment was discontinued after four cycles. This case highlights a rare presentation of MZL, mimicking the features of phymatous acne rosacea, particularly rhinophyma and otophyma. The resemblance to rosacea, particularly phymatous subtypes, leads to initial misdiagnosis and delays in appropriate treatment. This underlines the importance of considering alternative diagnoses in patients with atypical or nonresponsive dermatological conditions, especially when conventional therapies fail. Early biopsy and histological evaluation are critical for ensuring timely diagnosis and treatment, potentially improving patient outcomes.