Presentation
Abdominal pain and blood loss.
Patient Data
Oval soft tissue mass centered on the distal ileum. This does not obstruct the small bowel. No adenopathy, peritoneal nodularity, or solid organ metastasis. No free fluid.
PATHOLOGY REPORT:
SPECIMEN(S) SUBMITTED: SMALL BOWEL MASS
GROSS DESCRIPTION: The specimen consists of a 13.5 cm somewhat tortuous segment of small bowel with prominant thickening of the mid portion including involvement of the sigmoid mesentery. The specimen is opened revealing a 10 cm exophytic and lobulated tan tumor. On cut section there is prominant fibrinopurulent debris within the tumor. Grossly the tumor extends through the muscularis propria into the peri-intestinal adipose tissue and is located 1.0 cm from the mesenteric margin. No obvious serosal involvement is indentified. The majority of the tumor is soft, pink-tan and grossly necrotic.
MICROSCOPIC DESCRIPTION: The tissue is examined microscopically. Sections of the tumor show a neoplastic proliferation of moderately differentiated glandular elements with moderate amounts of eosinophilic cytoplasm and basally located round to irregular nuclei with small nucleoli. Interspersed with the glandular elements is a sarcomatoid spindle cell component arranged in interweaving fascicles. There are also more widespread areas consisting solely of the sarcomatous component. The sarcomatoid cells vary from small and bland spindled cells to markedly enlarged cells with prominent multinucleation. Frequent mitotic figures are present in the sarcomatoid component. Immmunohistochemical staining shows strong positive staining in the glandular component for pan-keratin and CK7 and no staining for CK20, TTF-1 or CD117 (c-kit). The sarcomatoid component shows rare cells positive for CK20 and no staining for pan-keratin, CK7, TTF-1, smooth muscle myosin heavy chain or CD117 (c-kit).
DIAGNOSIS
A) SMALL BOWEL, PARTIAL RESECTION
- SARCOMATOID CARCINOMA (CARCINOSARCOMA) (10.0 CM TUMOR DIAMETER) LOCATED
1.0 CM FROM THE CLOSEST (MESENTERIC) MARGIN.
- NO PERINEURAL OR LYMPHOVASCULAR INVASION IDENTIFIED.
- SINGLE LYMPH NODE IDENTIFIED, NEGATIVE FOR TUMOR (0/1).
Case Discussion
This is an extremely rare malignant neoplasm of the small bowel with a very poor prognosis. Only about 30 cases have been reported to date.
More commonly, small bowel tumors are adenocarcinoma, carcinoid, mesenchymal (such as GIST), and lymphoma. Given the relatively bland imaging features and lack of small bowel obstruction, lymphoma was favored in this case. Sarcomatoid carcinomas have histologic features of carcinoma and sarcoma. Aggressive surgical management is the primary treatment modality.
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