Facial nodule in a 34-year-old man.

A 34-year-old man presented with an asymptomatic nodular mass on his right cheek of two years′ duration [Figure 1]. It initially appeared as a small papule that gradually increased to its present size. Physical examination revealed a firm, nontender bilobed tumor measuring 2.5 × 2 × 1 cm in size. There was no cervical lymphadenopathy. The tumor was mobile and distinct from surrounding structures. The differential diagnosis of dermatofibroma, pilomatricoma, and sebaceous cyst were considered. Surgically excised nodule was sent for histopathological examination. The patient was advised to come for follow-up.

Figure 1

A solitary bilobed nodule on the cheek

Microscopic examination of the excised lesion showed a well-circumscribed tumor located in the deep dermis and seen extending into subcutaneous tissue [Figure 2]. A biphasic growth pattern could be readily appreciated and consisted of epithelial component embedded in a mixture of abundant fibrous and myxochondroid stroma [Figure 3]. The epithelial component consisted of branching and nonbranching tubules, cords, and dilated cystic structures with secretions in their lumina. The tubules demonstrated an eccrine differentiation, with lining of luminal layer with cuboidal cells and a peripheral layer of flattened cells. The peripheral layer of cells merged with the stroma that stained strongly with alcian blue.

Figure 2

well-circumscribed dermal nodule. (H and E, × 40)

Figure 3

Biphasic tumor composed of myxochondroid stroma and epithelial component. (H and E, × 200)

Question

What is your diagnosis?

Answer

Chondroid syringoma

Discussion

Chondroid syringoma (CS), also called as mixed tumor of skin, is a benign cutaneous adnexal tumor composed of epithelial and stromal elements and is predominantly seen in the head and neck regions. Its incidence is less than 0.01% among the primary skin tumors.[1] There is a male predilection and they clinically present as a solitary slow-growing, nontender, firm, and mobile dermal or subcutaneous nodule. Their size ranges from 0.5 to 3.0 cm, with very large ones having a propensity for malignant transformation.

Neoplasms with microscopic features that indicate both epithelial and mesenchymal origin have been referred to as mixed tumors. Bilroth in 1859 first described a mixed tumor of the skin that is analogous to the mixed tumors of salivary gland. Hirsch and Helwig in 1961[2] introduced the term CS to describe the tumor that is characterized by the presence of sweat gland elements lying within the cartilaginous stroma. They are clinically not distinct and diagnosed only after microscopic examination.[3] The epithelium often shows a pattern of branching tubules with eccrine or rarely apocrine differentiation. The stroma may be myxoid, chondroid, fibrous, or more commonly, a combination of these. Immunohistochemical staining reveals staining of inner epithelial layer with cytokeratin, Epithelial Membrane Antigen and Carcinoembryonic Antigen while the outer layer stains with S100 and vimentin.

CS are usually benign but may rarely undergo malignant transformation.[45] The malignant forms may arise de novo[4] or may arise from incompletely excised lesion that has recurred.[5] Although the diameter of malignant CS is usually more than 3 cm (range, 2–8 cm; mean, 4.8 cm), giant benign facial CS have also been reported.[6] Therefore, lesions more than 3 cm in diameter should be followed up carefully on account of malignancy. The choice of management is complete surgical excision with a cuff of normal tissue, rather than simple shelling of lesion. To conclude, CS should be considered in the differential diagnosis of a nodular lesion on the skin of head and neck regions. Due to its rarity, the diagnosis is often overlooked, especially when considered preoperatively.