Chondroid syringoma is a rare nonmelanoma skin tumor of the head and neck, mostly benign in nature but with malignant potential. Predominantly, it presents in males as an asymptomatic, slow-growing, nontender nodule.2 Malignant chondroid syringomas are more rare, typically appear on the trunk and legs of females, and present as rapidly growing hard nodules. They can arise de novo or from a preexisting chondroid syringoma and can metastasize.3,4
Clinically and histologically, chondroid syringoma resembles a pleomorphic adenoma. Its diagnosis is dependent on the clinical location to exclude origin in a salivary gland.5 Folliculosebaceous and myoepithelial differentiation within the tumor has been reported.6 Immunocytochemistry is the same in both types and is used to identify 2 prominent components—epithelial and mesenchymal—found in both chondroid syringoma and pleomorphic adenoma. Immunocytochemistry differentiates the epithelial component, which expresses cytokeratin, epithelial membrane antigen, and carcinoembryonic antigen. In contrast, the mesenchymal component expresses S-100, vimentin, and neuron‐specific enolase, and less often glial fibrillary acidic protein, smooth muscle actin, calponin, or p63.5,7,8 Identification of both layers is a distinctive trait of both tumors, rendering it apart from other conditions in the differential diagnosis.5
Typical treatment options include excision, electrodesiccation, dermabrasion, and argon or CO2 laser. Total excision is recommended if there is a benign tumor and complete excision is a cure.2 One case of recurrent benign chondroid syringoma was treated by Mohs micrographic surgery on the eyebrow9; however, Mohs surgery was not recommended in our case due to concerns of spread if malignant as well as an unknown tumor depth, as these tumors have a tendency for deep infiltration.
Due to its anatomical location and presentation as an anterior preauricular mass, it was difficult to differentiate between chondroid syringoma from sweat gland origin and pleomorphic adenoma from the salivary gland. As seen in our case, it is important for physicians to be aware of the differential diagnosis for mixed tumors because it can have a notable effect on the type of surgical therapy and follow-up management.