Presentation
Weight loss. Iron deficient anemia.
Patient Data
Widespread lymphadenopathy at the right axilla, mediastinum and both hila. Numerous bilateral pulmonary nodules/masses with a basal predominance.
Circumferential ascending colon thickening with a large serosal-mass with low density centrally. Ileocolic and para-aortic lymphadenopathy. Two low density hepatic lesions. Left adrenal nodule.
Thickening and nodularity of the left anterior perirenal fascia. Left omental nodule. No ascites. Left adnexal cysts.
The patient presented to the emergency department with increasing abdominal pain two weeks later.
Ascending colon circumferential thickening. Cecum and terminal ileum are newly distended with fluid. Serosal mass has increased in size as has the ileocolic and para-aortic lymphadenopathy.
Right liver hypodensities have increased in size with new segment 4 and 7 hypodensities.
Left adrenal nodule is increased in size.
Increased left anterior perirenal fascial thickening. Left omental nodule is increased in size.
Left adnexal hypodensity is increased in size.
Basal pulmonary metastases.
The patient was taken to theater for emergency laparotomy for malignant large bowel obstruction. A right hemicolectomy was performed.
HISTOPATHOLOGY
MACROSCOPIC: Right hemicolectomy. The adjacent mesenteric fat demonstrates a cream nodular tumor on its surface up to 40 x 20mm. Posteriorly, a plane of resection is identified involving the posterior aspect of the ascending colon and adjacent mesenteric fat. Within the ascending colon is a near circumferential partially obstructing tumor. On sectioning the tumor invades through the muscularis propria into the adjacent mesenteric fat to communicate with what appears to be a conglomerate of macroscopically involved lymph nodes.
MICROSCOPIC FEATURES:
Histological description: Sections show a high grade carcinoma arising within the ascending colon. The carcinoma is comprised of relatively undifferentiated, markedly atypical tumor cells arranged in discohesive sheets, nests and infiltrative single cells. Many cells have a rhabdoid morphology, with eosinophilic eccentric cytoplasm. Extremely focal gland formation is present (block K). The tumor cells have pleomorphic nuclei with enlarged, hyperchromatic, bizarre forms present. Mitotic figures are numerous with atypical mitoses readily identified. The tumor is widely invasive and extends beyond the muscularis propria into the mesenteric fat, to involve the serosal surface of the mesentery. Extensive areas of tumor necrosis are present. The tumor displays extensive lymphatic and extra mural venous invasion. Numerous lymph nodes show evidence of metastatic carcinoma, the metastatic carcinoma within lymph nodes shows more prominent evidence of gland formation.
Ancillary tests/Immunohistochemistry:
Only very occasional rhabdoid cells show weak positive staining for the broad spectrum cytokeratin AE 1/AE 3 with characteristic diffuse positive staining of the cytoplasm for vimentin. Examination of INI1 protein expression shows retained expression. Loss of expression is associated with pure rhabdoid tumors whereas composite tumors, such as this case, rarely show loss of expression.
SUMMARY:
Specimen label: Right hemicolectomy.
Tumor site: Ascending colon.
Histological tumor type: Carcinoma with sarcomatoid (rhabdoid) component.
Nodes: 17 out of 20 lymph nodes show metastatic carcinoma/
Case Discussion
Colorectal adenocarcinomas with a sarcomatoid component are a rare subtype that present with large tumors. Patient's have a poorer prognosis than other subtypes. The aggressiveness of this tumor can be demonstrated by the marked increase in metastatic disease in just 2 weeks between scans.
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