Abstract
Mucoepidermoid carcinoma is a common malignant neoplasm of the salivary glands. Primary cutaneous mucoepidermoid carcinoma is rare, but mucoepidermoid carcinoma can also involve cutaneous sites as metastatic lesions. We present a case of an 82 year-old man with a history of a mucoepidermoid carcinoma of the larynx status post radiation therapy and salvage laryngectomy. Molecular studies showed an absence of MAML2 translocation in the larynx tumor. Two years following the primary larynx tumor resection, the patient presented with a two-month history of a growing ulcerated, firm nodule of the right flank with a clinical differential that included metastasis versus primary skin malignancy. Biopsy and subsequent excision of the flank tumor were performed and histological sections showed a basaloid carcinoma with extensive squamous differentiation. Additional sections of tumor revealed rare foci of mucinous differentiation. Molecular sequencing studies performed showed shared mutations between the patient's prior larynx salivary gland malignancy and the flank tumor, including a FBXW7 nonsense variant and deletion of CDKN2A. The flank tumor was also negative for a MAML2 translocation. The overall histological features and molecular profile were consistent with metastasis from the patient's mucoepidermoid carcinoma. This case highlights a metastatic mucoepidermoid carcinoma with unusual tumor histology composed predominantly of basaloid cells with extensive squamous differentiation and rare mucinous cells. Additionally, molecular profiling helped to support the diagnosis of a metastasis when histomorphological features differed between primary and metastatic lesions.
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