Malignant Chondroid Syringoma: An Extremely Rare Malignant Skin Adnexal Tumor

Malignant chondroid syringoma (MCS) is an extremely rare skin appendageal tumor. Early diagnosis and treatment are crucial due to frequent local recurrence and metastasis. A 29-year-old male presented with a walnut-sized, firm, and slightly movable cystic mass on his right cheek that has been present for 6 months. He had undergone a simple excision 1 year prior, with a diagnosis of chondroid syringoma with possible malignancy. However, the tumor recurred below the scar. Excisional biopsy revealed cuboidal cells with high cellularity, pleomorphism, nuclear atypia, infiltrative growth, and increased mitosis, consistent with the diagnosis of MCS. Following the confirmation of no metastasis, wide excision with 2 cm lateral margin was performed. The right zygomaticus major muscle was partially included as the basal resection margin. Due to the close proximity of the tumor nest to the basal margin (0.1 mm), adjuvant radiotherapy (RT) was administered. The lesion resolved with no recurrence following RT.