Conventional Versus Giant Basal Cell Carcinoma, a Review of 57 Cases: Histologic Differences Contributing to Excessive Growth

Abstract

Background: Giant basal cell carcinoma (GBCC) is defined as a basal cell carcinoma (BCC) exceeding 5 cm in size. While these tumors impart significant morbidity due to local tissue destruction and have a higher rate of metastatic disease than their conventional (smaller) counterparts, reasons for their large size remain unclear. While theories relating to neglect or faster growth rate are often invoked; to date, there has not been a comprehensive evaluation of the histologic features of these large tumors that may contribute to their size.

Methods: Histologic features of GBCCs (n = 29) were evaluated and compared to those of conventional BCC (n = 28). Available clinical demographic data were also reviewed.

Results: GBCCs, in addition to overall larger size, more often were thicker, displayed ulceration, and showed a more infiltrative growth pattern than their conventional counterparts. These rare tumors also displayed an insignificant increased propensity for a brisk host immune response, and the infiltrate significantly more often included clusters of plasma cells.

Conclusions: Most histologic features seen in GBCCs likely reflect their large size. Histologic features alone are unlikely to explain the size of these rare tumors. The possibility of an altered host immune response contributing to the growth of these tumors requires further investigation.

Keywords: Basal cell carcinoma; giant basal cell carcinoma; host immune response; plasma cells.

Figure 1

This conventional basal cell carcinoma is of the nodular subtype (Case 8) (H and E, ×100)

Figure 2

This giant basal cell carcinoma shows an infiltrative growth pattern, seen here invading as micronodules and infiltrative cords through atrophic skeletal muscle (Case 10) (H and E, ×100)

Figure 3

A conventional basal cell carcinoma, nodular and infiltrative subtypes, showing focal ductal differentiation within tumor nests (Case 1) (H and E, ×100)

Figure 4

This conventional basal cell carcinoma displays the focal presence of matrical differentiation as evidenced by trichohyaline granules (Case 34) (H and E, ×200)

Figure 5

Tumor infiltration of a large caliber nerve is seen in this example of giant basal cell carcinoma (Case 18) (H and E, ×200)

Figure 6

Tumor cell pleomorphism was detected in a subset of tumors, as seen in this example of a giant basal cell carcinoma. Tumor cell necrosis is also present (Case 46) (H and E, ×400)

Figure 7

Plasma cells were more commonly seen as part of the host response in giant basal cell carcinomas (Case 5) (H and E, ×200)

Figure 8

This giant basal cell carcinoma demonstrates large numbers of plasma cells, including some that have intracytoplasmic Russell bodies (immunoglobulin inclusions) (Case 30) (H and E, ×400)