Diagnostic Challenges of Sinonasal Pleomorphic Adenoma

Pleomorphic adenomas (PAs) are benign tumors of the salivary glands. Rarely, they arise in the sinonasal cavity, presenting as well-defined, homogeneous soft tissue masses, causing expansive bony changes. The significance of PAs is the possibility of giving rise to malignant carcinoma - "carcinoma ex-pleomorphic adenoma" (CXPA).Here, we present the case of a 64-year-old female complaining of progressive unilateral congestion and external nose deformation, mostly along the left contour of the radix, with epiphora of the ipsilateral eye. Eventually, a tumor began protruding from the left naris. The computed tomography excluded osteolysis, while the surgical procedure discovered the inferior turbinate as the origin of the tumor. In addition, the ipsilateral maxillary sinus was found to have developed secondary sinusitis. After complete surgical excision, the histological result was sinonasal melanoma, but following no progression of the disease, a second pathologist with additional immunohistochemical markers (HMB-45 (human melanoma black 45) negative, Melan-A (melanoma antigen recognized by T-cells 1) negative, S100 (protein soluble in 100% ammonium sulfate at neutral pH) positive, panCK AE1/AE3 (pan cytokeratin antibodies AE1 and AE3) negative, p63 (tumor protein 63) negative, Ki-67 (marker of proliferation Kiel 67) 10%, CD68 (cluster of differentiation 68) negative, CK7 (cytokeratin 7) negative, and CDX2 (caudal-type homeobox 2) negative) placed the definitive diagnosis of PA.PA of the inferior turbinate is an extremely rare finding, with the clinical symptoms being unspecific. Sometimes, SOX-10 (SRY-box transcription factor 10) positivity can mislead to malignant melanoma, as in our case, which is why a broad panel of immunohistochemical markers is critical for the definitive diagnosis.