Basal Cell Carcinoma With Calcification: Case Report of Calcifying Basal Cell Carcinoma and Review of Calcinosis Cutis Associated With Basal Cell Carcinoma

Abstract

Basal cell carcinoma is the most common cutaneous neoplasm. Calcinosis cutis is the deposition of calcium within the dermis. An 80-year-old man presented with a pearly nodule on his left nasal ala; a shave biopsy confirmed the diagnosis of a nodular basal cell carcinoma with calcinosis cutis, which was removed with Mohs micrographic surgery. The incidence of basal cell carcinoma with calcinosis cutis as well as the classification, identification, and potential origin of calcium deposits in basal cell carcinoma are discussed. Basal cell carcinoma can be associated with calcinosis cutis; indeed, calcifying basal cell carcinoma has a calculated incidence of 14%. There are five categories of calcification in basal cell carcinoma. In addition, calcification observed in cancer-free initial sections of a suspected basal cell carcinoma may be a diagnostic clue that a neoplasm is present in deeper sections of the tissue specimen. Although nodular basal cell carcinoma has the greatest incidence (37%) of calcium deposition, infiltrative (29%) and micronodular (27%) basal cell carcinomas are also frequently associated with calcification; therefore, the presence of calcifying basal cell carcinoma may indicate a more aggressive tumor subtype. Basal cell carcinoma may also be suspected in the differential diagnosis of a superficial breast neoplasm in which calcification is observed in the dermis; in this situation, mammography has been an effective diagnostic approach for identifying the basal cell carcinoma with calcification. The pathogenesis of calcification in basal cell carcinoma remains to be definitively established; however, calcium-binding proteins found in poorly differentiated keratinocytes may contribute to the etiology of basal cell carcinoma with calcification. The treatment of basal cell carcinomas with calcinosis cutis is similar to that of non-calcifying basal cell carcinomas; it is based upon the histologic subtype, the size, and the location of the tumor.

Keywords: basal; calcification; calcinosis; calcium; carcinoma; cell; cutis; histology; mammography; nodular.

Figure 1. Clinical presentation of calcifying basal cell carcinoma and removal with Mohs microscopically controlled surgery

An 80-year-old man presented with a nodule on his left nasal ala (A); the tumor is surrounded by red arrows, and the biopsy site is the skin within the purple oval. The lesion site was injected with epinephrine-containing anesthetic before the shave biopsy, accounting for whitening of the surrounding tissue. The biopsy site (B) was healed at four weeks follow-up (black circle), and Mohs surgery was scheduled to excise the nodular basal cell carcinoma with calcinosis cutis (surrounded by red arrows). After three stages of Mohs micrographic surgery, clear tumor margins were obtained; the resulting skin defect on the left nasal ala is surrounded by red arrows (C). A skin-advancing flap was initially planned (purple lines demarcating the planned incisions) to close the nasal defect (D); however, a full thickness skin graft (surrounded by red arrows) from posterior auricular skin was used instead.

Figure 2. Histologic sections of a nodular basal cell with three areas of calcification

The biopsy tissue specimen was bisected. One half of the bisected specimen shows three areas of calcification within the dermis (red, black, and green circles) associated with areas of basal cell carcinoma (A). A closer view (B) shows type 4 basal cell carcinoma-associated calcification free in the adjacent dermis (red circle). A closer view (C) shows type 5 basal cell carcinoma-associated calcification (black arrow) with calcium in a hair follicle (black circle). A closer view (D) shows a type 3 basal cell carcinoma-associated calcification (green arrow) with calcium in an area of necrosis (blue arrow) within an aggregate of basal cell carcinoma (green circle).

Figure 3. Histologic sections of a nodular basal cell carcinoma with one area of calcification

The second half of the bisected tissue specimen shows one area of calcification within a nest of basal cell carcinoma (A). A closer view (B) shows a type 1 basal cell carcinoma-associated calcification (red arrow) with calcium in the aggregate of basaloid tumor cells (red circle). Stromal retraction (green arrow) is seen between the nest of tumor cells and the adjacent dermis.