Basal Cell Carcinoma with Sebaceous Differentiation.

Sir,

Basal cell carcinoma (BCC) is a malignant neoplasm of abnormal folliculosebaceous-apocrine germinative cells, constituting approximately 70% of all keratinocyte tumors. It commonly affects the head and neck region.[1] BCC with sebaceous differentiation is a rare histopathological variant.[23]

A 42-year-old male presented with a solitary asymptomatic nodular swelling having erosion and crusting of the overlying skin close to the left nasolabial fold. There was history of a small pigmented lesion at the same site since childhood, which had increased in size with change in appearance for the last 3 months. He was a known hypertensive for the past 10 years and was on medication for the same. His medical history was otherwise unremarkable.

Cutaneous examination revealed a skin-colored nodule of 1 cm × 1.5 cm in size just below the left nasolabial fold with overlying crusting and telangiectasia [Figure 1]. Considering the morphology of the lesion, differential diagnoses of nodular BCC and keratoacanthoma were considered. Skin biopsy from the nodular lesion revealed the presence of poorly circumscribed tumor masses in the dermis with peripheral palisading of basaloid cells along with retraction artefacts. Higher magnification revealed nodular collection of basaloid cells separated by fibrous septae. These nodules contained tubular laminae lined by cornified cells having a crenulated inner surface as well as sebaceous differentiation with the presence of sebocytes. Final diagnosis of BCC with sebaceous differentiation was made [Figures 2–4]. The patient underwent surgical excision with 5-mm margin under local anesthesia. The margins of the excised specimen were devoid of tumor cells. Even after 2 years of follow-up, there is no recurrence of the tumor.

Figure 1

Well-defined nodular swelling just above the left side of the upper lip with crusting and telangiectasia

Figure 2

Histopathology, acanthosis, papillomatosis, lymphohistiocytic infiltrate with evidence of tumor mass in the dermis with basaloid cells in palisading arrangement with retraction artefacts (H and E, 40×)

Figure 4

Vacuolated cells with foamy, bubbly cytoplasm, which are suggestive of features of sebocytes (H and E, 400×)

Nodular collection of basaloid cells separated by fibrous septa along with tubular lamina lined by crenulated inner surface (H and E, 100×)

BCC is a malignant neoplasm derived from abnormal folliculosebaceous-apocrine germinative cells.[] BCC with sebaceous differentiation is a rare presenatation with very few reports.[2]

Histopathological examination of a BCC with sebaceous differentiation usually reveals poorly circumscribed neoplasm invading the deep dermis composed of columnar basaloid cells having slightly elongated nuclei aligned in a palisade at the periphery, retraction clefts between the stroma and tumor aggregates, and sebaceous duct-like structures. Vacuolated cells, with foamy, bubbly cytoplasm and scalloped or starry nuclei, suggestive of sebocytes are scattered within the tumor masses. These vacuolated cells are immunohistochemically positive for epithelial membrane antigen (EMA).[4]

The criteria for the diagnosis of this tumor are variably defined by various authors. BCC with sebaceous differentiation is differentiated from sebaceous adenoma by a germinative cell component which occupies greater than 50% of the transverse diameter of tumor lobules that typically manifest a rounded morphology with areas of slit-like retraction and accompanied by mitoses and apoptotic debris. Unlike sebaceous carcinoma, there is no evidence of pagetoid spread in the overlying epidermis, haphazard infiltrative growth morphology, desmoplastic stromal reaction, and invasion of adjacent structures.

In constrast, sebaceous adenoma is characterized by a lining of germinative cells less than 50% of the diameter of the neoplastic lobule whereas sebaceous hyperplasia typically has a peripherally disposed layer of germinative cells, typically 1–2 cells thick. On the other hand, sebaceoma manifests a haphazard array of germinative epithelium admixed with sebocytes and structures that recapitulate sebaceous ducts.[5] Differentiating features between BCC with sebaceous differentiation, sebaceoma, and sebaceous carcinoma are listed in Table 1.[12678910]

Table 1

Differentiating features between BCC with sebaceous differentiation, Sebaceoma and Sebaceous carcinoma

BCC is a malignant neoplasm with rare variants of apocrine or follicular or sebaceous differentiation.[4] The rarity of BCC with sebaceous differentiation may be attributed to the ambiguous nomenclature of sebaceous neoplasms in the past and low awareness about this presentation. BCC with sebaceous differentaition usually does not have an adverse prognosis.

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Conflicts of interest

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