Sarcomatoid Basal Cell Carcinoma—Predilection for Osteosarcomatous Differentiation

Abstract

Primary cutaneous carcinomas rarely show heterologous malignant mesenchymal differentiation. We report 11 cases of sarcomatoid basal cell carcinoma (BCC) with osteosarcomatous differentiation. The patients (7 men and 4 women) ranged in age from 61 to 92 years (median 75 y). The tumors presented as exophytic nodules (0.3 to 7 cm) on the head (n=6), upper limb (n=3), and lower limb (n=2). All lesions were completely excised. Seven patients were alive without evidence of disease (follow-up interval 5 to 24 mo) and 1 patient died of unrelated causes at 7 months without evidence of disease. On histology, the tumors were dermal in location with 2 cases showing focal subcutaneous involvement. Ten tumors were well-circumscribed and 1 tumor showed focally infiltrative edges. Ten tumors revealed conventional BCC associated with varying proportions of osteosarcomatous and undifferentiated sarcomatous stroma. Transition from neoplastic epithelial to mesenchymal cells was seen in 8 cases. One case showed a purely osteoclastic giant cell rich malignant mesenchyme, interpreted as representing early stages of osteosarcomatous transformation. Previously unreported in sarcomatoid BCC, the mesenchymal component of another two cases displayed predominant malignant giant cell tumor like areas and 1 further case disclosed areas reminiscent of telangiectatic osteosarcoma. Pancytokeratins (AE1/3 and MNF116) and smooth muscle actin stained occasional undifferentiated sarcomatous cells in 2 and 3 tumors, respectively. MNF116 and EMA were focally positive in osteosarcomatous tumor cells of 1 case. Although the follow-up interval is short, our data suggest an excellent prognosis for polypoid and exophytic sarcomatoid BCC after complete surgical resection.

Basal cell carcinoma with a sarcomatous component (carcinosarcoma): A series of 5 cases and a review of the literature

“…We, therefore, extracted all the BCC cases from previous reports and the data would suggest that these lesions behave less aggressively than similar tumors with a squamous or adnexal epithelial component. 10,11,16 Indeed, of the 27 reported cases of this particular group, there have been only two cases where metastasis has occurred. Both of these tumors were particularly unusual in terms of presentation site, stromal components, or size at presentation, which may indicate why they behaved more aggressively.…”

“…However, the subtype of BCC is rarely described in other reported cases of carcinosarcoma. McMenamin et al 16 presented 11 cases with a BCC epithelial component, none of which demonstrated recurrence or metastasis where follow-up data were available. The BCC subtypes for these patients comprised infiltrative, nodulocystic, adenoid, micronodular, and superficial.…”

High-grade Trichoblastic Carcinosarcoma

“…If one is strict with the terminology, then the majority of the so-called carcinosarcomas in many organs should be called metaplastic (sarcomatoid) carcinomas, including those reported in the skin. [3][4][5][6] Authentic carcinosarcomas are rare, and with the development of molecular genetic techniques it becomes obvious that many of the so-called carcinosarcomas, in fact, represent metaplastic (sarcomatoid) carcinomas because they are monoclonal in origin, and their mesenchymal component is likely to be derived from the epithelial component. [7][8][9][10][11][12][13] An example of a seemingly authentic cutaneous carcinosarcoma, designated trichoblastic carcinosarcoma, was reported in 2004.…”

Merkel Cell Carcinoma With Glandular Differentiation Admixed With Sweat Gland Carcinoma and Spindle Cell Carcinoma

“…15 Sarcomatoid carcinoma of the skin is most commonly heterologous mesenchymal differentiation in a background of squamous cell carcinoma followed in frequency by basal cell carcinoma. 16 MCC with biphasic differentiation of embryonal rhabdomyosarcomalike spindle cells has previously been reported as Merkel cell carcinosarcoma. 17 We describe a unique case of MCC with triphasic phenotypic differentiation features showing sweat gland carcinoma (sweat gland Ca.)…”