Sarcomatoid Carcinoma of the Gallbladder With a Rhabdoid Tumor Component Open Access

Sarcomatoid carcinoma is an extremely rare neoplasm in the gallbladder, although it is occasionally reported in other sites, including the uterus, liver, lung, breast, kidney, and ovary.1 To our knowledge, only 29 cases of sarcomatoid carcinoma of the gallbladder have been reported in the English literature. Sarcomatoid carcinomas are composed of malignant epithelial and sarcomatous components, sometimes with heterologous sarcomatous elements. The latter can be an osteosarcoma,2,3 a chondrosarcoma,2–6 or a rhabdomyosarcoma.2,3,7 However, to our knowledge, a sarcomatoid carcinoma with a rhabdoid component has not been reported in the gallbladder. We present a case of sarcomatoid carcinoma showing focal but distinct adenocarcinoma and rhabdoid tumor components. The rhabdoid tumor cells contained eosinophilic hyaline globules in the cytoplasm and eccentric nuclei with prominent nucleoli. Immunohistochemical and electron microscopic studies of the rhabdoid component were performed.

A 61-year-old woman presented with a 5-month history of intermittent right upper quadrant pain, anorexia, and weight loss. A physical examination revealed a nontender and hard mass in the right upper quadrant of her abdomen. Laboratory examinations showed a normal leukocyte count, normal hemoglobin levels and liver function tests, and a normal urine analysis. The serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9 were within the normal reference range. Her family history was unremarkable, as was her medical history, except for a liver abscess 10 years earlier.

The ultrasonographic examination showed a 5-cm irregularly shaped heterogeneous mass in the gallbladder (Figure 1, B). The computed tomographic scan showed a focal wall thickening in the neck portion of the gallbladder (Figure 1, A). A preoperative diagnosis of gallbladder cancer was made, and a cholecystectomy with a common bile duct resection was performed.

The specimen showed an ill-defined firm mass (4.5 × 4 × 4 cm) obstructing the lumen in the neck portion of the gallbladder, with the tumor exposed to the serosa. The cut surface of the mass was firm, solid, yellowish gray, and granular with focal areas of necrosis (Figure 2). Microscopically, the tumor was biphasic and composed of sarcomatous and adenocarcinomatous components. The sarcomatous area consisted of diffusely arranged large and pleomorphic cells with rhabdoid tumor cells, scattered tumor giant cells, and multifocal areas of necrosis admixed with neutrophils and lymphocytes (Figure 3, A). Numerous mitoses including bizarre, atypical forms were present in the pleomorphic tumor cells. The rhabdoid tumor cells showed abundant eosinophilic cytoplasm with hyaline globules and eccentric nuclei with prominent nucleoli (Figure 3, B). Carcinomatous areas composed of solid cords or glands with infiltrating tumor cells showed focal mucin production (Figure 3, C). Carcinomatous components were intermingled with sarcomatous components in some areas. Heterologous sarcomatous elements were not identified.

By immunohistochemical staining, we determined that the sarcomatous component was positive for vimentin (1:2000; Zymed, San Francisco, Calif) only. The carcinomatous component was positive for cytokeratin (CK; 1:200; Zymed) but was negative for other markers. The rhabdoid tumor cells coexpressed CK (Figure 3, D) and vimentin (Figure 3, E) but were negative for desmin (1:200; Dako Corporation, Glostrup, Denmark) and myoglobin (1:4000; Dako). An electron microscopic study was performed from the formalin-fixed and paraffin-embedded tissue, and the rhabdoid tumor cells showed cytoplasmic whorls or aggregates of intermediate filaments in the cytoplasm and eccentric nuclei (Figure 4).

Two months after surgery, the patient visited the hospital because of a mild fever and tenderness on the operation site. A follow-up computed tomographic scan showed multiple intrahepatic metastases and omental seedings. She could not receive any treatment for cancer because of her poor general medical condition.

Sarcomatoid carcinoma composed of epithelial and sarcomatous components is an extremely rare neoplasm in the gallbladder. The epithelial components usually consist of an adenocarcinoma with an occasional squamous cell carcinoma.4 The sarcomatous components consist of undifferentiated spindle or stellate cells1,4,6,8–10 with a variable proportion of heterologous components. The histology of the sarcomatous area includes spindle cell sarcoma,1,4,6,8–10 fibrosarcoma,2 myxochondrosarcoma, and fibrochondromyxosarcoma.

To our knowledge, 29 cases of sarcomatoid carcinoma have been reported in the gallbladder. Sarcomatoid carcinomas of the gallbladder are known to occur in elderly women (mean age, 67 years), often with abdominal tenderness, jaundice, and a right upper quadrant mass. They are associated with gallstones 75% of the time. Most sarcomatoid carcinomas are exophytic and polypoid and distend the gallbladder fundus.11 The initial treatment has been a cholecystectomy with or without a bile duct resection, but a curable resection has usually not been feasible because of advanced disease presentation. The prognosis of this tumor is very poor.3,5,9,11 

Three of the 29 cases of sarcomatoid carcinoma of the gallbladder in the literature contained a rhabdomyosarcomatous component with occasional cytoplasmic cross-striation and myoglobin positivity.2,3,7 The rhabdoid cells in our case did not show any myogenic differentiation by electron microscopic and immunohistochemical studies, which suggests that they were not true rhabdomyoblasts. So-called “rhabdoid cells” have been found in various types of neoplasms, including carcinomatous and sarcomatous neoplasms.12,13 In the gallbladder, rhabdoid tumor differentiation in sarcomatoid carcinoma has not been reported.

A few cases of sarcomatoid carcinoma in the gastrointestinal tract have been reported in the literature.11,14,15 The rhabdoid tumor of the gastrointestinal tract presents as a sarcomatoid carcinoma with variable amounts of carcinomatous and sarcomatous components. A rhabdoid tumor of the gastrointestinal tract has a very poor prognosis with early metastases.14,15 The present case appears to have a poor prognosis because the patient initially presented with a locally advanced tumor involving the serosa, and a follow-up computed tomographic scan demonstrated multiple intrahepatic and omental metastases.

The histogenesis of sarcomatoid carcinoma with rhabdoid tumor components has been controversial, as has its name. Some investigators have called such neoplasms “malignant mixed tumors,” analogous to mixed müllerian tumors of the uterus. The tumor has sometimes been called a “carcinosarcoma,” referring to the dual differentiation of carcinoma and sarcoma. Others have called it a “sarcomatoid carcinoma” and suggested that the sarcomatous components represent metaplastic or dedifferentiated carcinoma cells.

Immunohistochemical staining and electron microscopic findings are helpful in making the diagnosis. The tumor cells of the sarcomatous area coexpress CK and vimentin immunohistochemically, and ultrastructurally, they show desmosome-like junctions and aggregates of cytoplasmic intermediate filaments.6,10 These findings suggest an epithelial origin of the sarcomatous components. Our case showed diffusely arranged pleomorphic cells with occasional rhabdoid morphology and were positive for CK and vimentin but not for desmin and myoglobin; they also showed cytoplasmic whorls or aggregates of intermediate filaments with no skeletal muscle differentiation, which suggests a rhabdoid tumor component in sarcomatoid carcinoma.

In summary, we present a case of sarcomatoid carcinoma with a rhabdoid tumor component. Immunohistochemically, the rhabdoid tumor cells coexpressed vimentin and CK, and ultrastructurally, they contained whorls of intermediate filaments. To our knowledge, this is the first case of sarcomatoid carcinoma with a rhabdoid tumor component of the gallbladder. The patient was alive with metastatic disease 2 months after surgery.