A 33 year old man visited a local hospital because of jaundice. He was diagnosed as having gallbladder carcinoma based on a radiographic examination, and was referred to the National Cancer Centre, Tokyo, Japan. Laboratory data indicated that carcinoembryonic antigen, CA19-9, and elastase concentrations were within normal limits, and that T-bilirubin (51 mg/litre), D-bilirubin (37 mg/litre), alkaline phosphatase (688 IU/litre), glutamic oxaloacetic transaminase (84 U/litre), glutamic pyruvate transaminase (317 U/litre), lactate dehydrogenase (431U/litre), and the white blood cell count (9.6 × 109/litre) were slightly raised.
Abdominal computed tomography imaging showed partial infiltration of the tumour into the gallbladder wall. We tried to perform a percutaneous needle biopsy, but because adenocarcinoma could not be completely ruled out the use of undue force was considered dangerous. We performed a cytological examination which was unable to provide definitive information on the lesion. The preoperative diagnosis was a malignant neoplasm that probably originated from the neck of the gallbladder, cystic duct, or common bile duct. However, it is unusual for a carcinoma to grow so large without showing signs of invasion of the liver and portal vein (fig 1A). The differential diagnosis was an extranodal malignant lymphoma, and a hepatopancreatoduodenectomy was performed.
Figure 1 (A) Abdominal computerised tomography image showing partial infiltration of the tumour into the gallbladder wall but no sign of invasion of the liver or portal vein. (B) Macroscopically, the gallbladder lumen is (more ...)
Macroscopically, the gallbladder lumen was filled with blood and degenerative tissue, and the cut surface of the tumour had a nodular, well circumscribed, glistening appearance (fig 1B). The tumour measured 6.0 × 4.5 cm at its maximum diameter.
Microscopically, the tumour cells had various amounts of eosinophilic cytoplasm and medium sized round nuclei with indentation and grooving. They were arranged in a trabecular to sheet-like pattern within the thin fibrous septa (fig 2A), and did not show a cohesive growth pattern. The tumour cells had invaded the muscular layer of the gallbladder, but most of the gallbladder epithelium was intact (fig 2B). Tumour invasion was seen in the cystic duct, common bile duct, portal vein, part of the liver parenchyma, hepatoduodenal ligament, omentum, part of the muscular layer of the transverse colon, and duodenum. The histological differential diagnosis for such small round cell tumours included undifferentiated carcinoma, small cell carcinoma, Ewing’s sarcoma, rhabdomyosarcoma, monophasic synovial sarcoma, nephroblastoma, and haemopoietic tumour.
Figure 2 (A) The tumour cells have various amounts of eosinophilic cytoplasm and are arranged in a trabecular to sheet-like pattern (haematoxylin and eosin (H&E) stain; original magnification, ×400). (more ...)
Upon immunohistochemical examination, the tumour cells showed diffuse and strong reactivity for myeloperoxidase (MPO), CD43, and c-kit protein (CD117) (fig 2A–C), and weak reactivity for CD45 (LCA) and CD99. The cells were negative for CD20, CD79a, CD3, CD34, CD45RO (UCHL-1), CD68, CD56, terminal deoxynucleotidyl transferase, WT1, desmin, vimentin, and cytokeratins (CAM 5.2, AE 1/3, and KL1). Based on these results, we made a final diagnosis of EMMT.
After surgery, the patient underwent combination chemotherapy as prescribed for cases of acute myeloblastic leukaemia, but clinical investigations—including computerised tomography and a bone marrow trephine biopsy specimen—did not detect more lesions. The patient did not develop acute leukaemia during a follow up period of four years.