Sarcomatoid carcinomas of the gallbladder: clinicopathologic characteristics

Abstract

Sarcomatoid carcinomas recently came into the spotlight through genetic profiling studies and also as a distinct model of epithelial-mesenchymal transition. The literature on sarcomatoid carcinomas of gallbladder is limited. In this study, 656 gallbladder carcinomas (GBC) were reviewed. Eleven (1.7%) with a sarcomatoid component were identified and analyzed in comparison with ordinary GBC (O-GBC). Patients included 9 females and 2 males (F/M = 4.5 vs. 3.9) with a mean age-at-diagnosis of 71 (vs. 64). The median tumor size was 4.6 cm (vs. 2.5; P = 0.01). Nine patients (84%) presented with advanced stage (pT3/4) tumor (vs. 48%). An adenocarcinoma component constituting 1-75% of the tumor was present in nine, and eight had surface dysplasia/CIS; either in situ or invasive carcinoma was present in all cases. An intracholecystic papillary-tubular neoplasm was identified in one. Seven showed pleomorphic-sarcomatoid pattern, and four showed subtle/bland elongated spindle cells. Three had an angiosarcomatoid pattern. Two had heterologous elements. One showed few osteoclast-like giant cells, only adjacent to osteoid. Immunohistochemically, vimentin, was positive in six of six; P53 expression was > 60% in six of six, keratins in six of seven, and p63 in two of six. Actin, desmin, and S100 were negative. The median Ki67 index was 40%. In the follow-up, one died peri-operatively, eight died of disease within 3 to 8 months (vs. 26 months median survival for O-GBC), and two were alive at 9 and 15 months. The behavior overall was worse than ordinary adenocarcinomas in general but was not different when grade and stage were matched. In summary, sarcomatoid component is identified in < 2% of GBC. Unlike sarcomatoid carcinomas in the remainder of pancreatobiliary tract, these are seldom of the "osteoclastic" type and patients present with large/advanced stage tumors. Limited data suggests that these tumors are aggressive with rapid mortality unlike pancreatic osteoclastic ones which often have indolent behavior.

Keywords: Adenocarcinoma; Carcinoma; Gallbladder; Sarcoma; Sarcomatoid.

Figure 1:

Macroscopic photograph of a sarcomatoid carcinoma (A). Growth pattern was illustrated in this low power photomicrograph (B). In one case, the exophytic component of the tumor was an intracholecystic papillary tubulary neoplasm composed of compact papillary proliferation of preinvasive dysplastic lesion (C).

Figure 2:

Different sarcomatoid patterns are identified in sarcomatoid carcinoma of the gallbladder, including pleomorphic spindle cells (A), pleomorphic epithelioid cells (B). Infiltration of the sarcomatoid carcinoma cells into the vessel walls could be observed (C). Three cases had angiosarcomatoid pattern (D), also accompanied by inflammatory cells (E). In some areas, the tumor displayed whorl formation as well as collagenization pattern and plumb relatively uniform cells that are often seen in fibroblastic and fibrohistiocytic neoplasms (F). Eight patients had surface dysplasia/CIS in the surface epithelium; in this photomicrograph high grade dysplasia is depicted on the surface, with sarcomatoid carcinoma cells in the stroma (G). Osteoid formation could be seen (H), and in one case, this was accompanied by osteoclastic giant cells (I). Median Ki67 index was 40% (J). P53 expression was detected in all 6/6 of cases tested (K). CK18 was commonly retained in the sarcomatoid component (L).