Malignant rhabdoid tumor of rectum: report of a case

SMARCB1/INI1-Deficient Poorly Differentiated Carcinoma of the Colon With Rhabdoid Features-A Rare Tumor With Serrated Phenotype: Case Report and Review of Literature

Poorly differentiated colonic carcinoma with rhabdoid features is a rarely described entity. Our knowledge regarding the molecular phenotype of the tumor is evolving. We herein report a similar tumor with rhabdoid differentiation identified in the splenic flexure, which on histological examination showed a poorly differentiated phenotype with epithelioid to spindled morphology, tumor giant cells, and rhabdoid differentiation. The tumor was mismatch repair-proficient, deficient of INI1/SMARCB1, KRAS mutated (A146×), BRAFV600E mutated (c.1799T > A), and NRAS wild-type, indicating serrated differentiation in the tumor. The patient died after 3.5 months post-surgery. INI1-deficient poorly differentiated carcinoma of the colon is a rare, aggressive colonic malignancy showing a serrated phenotype. Routine identification and subtyping are important keeping in mind the distinct tumor phenotype, resistance to conventional chemotherapy, and dismal prognosis.

INI1-negative colorectal undifferentiated carcinoma with rhabdoid features and postoperative rapidly growing liver metastases: a case report and review of the literature

BACKGROUND

Malignant tumors with rhabdoid features are extremely rare. They can occur in various organs, including the gastrointestinal tract, with common clinical features of high malignancy and poor prognosis.

CASE PRESENTATION

A 41-year-old man visited our hospital complaining of lower abdominal pain and fever. Computed tomography (CT) revealed two wall-thickening lesions in the rectum and sigmoid colon, with the latter invading the small intestine and abdominal wall. Lymph nodes were swollen in the sigmoid mesocolon and at the roots of the inferior mesenteric artery. Colonoscopy revealed a circular type 3 lesion in the sigmoid colon and a semicircular type 2 lesion in the rectum. Biopsies of the sigmoid colon and rectum lesions revealed poorly and moderately differentiated adenocarcinoma cells, respectively. The sigmoid colon, rectum, invaded small intestine, and abdominal wall were resected; lymph node dissection was also performed. Histopathological finding of the sigmoid colon lesion revealed that the tumor cells had poor connectivity with each other, and each cell had eosinophilic cytoplasm and a polymorphic nucleus. These characteristics are termed rhabdoid features, because the morphology of these cells is similar to that of rhabdomyosarcoma tumor cells. Immunohistochemical examination showed that the tumor cells were positive for both epithelial (cytokeratin AE1/AE3) and mesenchymal cell markers (vimentin); however, they were negative for integrase interactor 1 (INI1). Therefore, the sigmoid colorectal cancer was diagnosed as an INI1-negative undifferentiated carcinoma with rhabdoid features. The patient continued to experience high fever after surgery; thus, we performed an abdominal CT scan that revealed cystic lesions in the liver 4 days after surgery. These were absent in the positron emission tomography (PET)-CT scan performed 14 days before surgery. These tumors grew rapidly, and fine needle aspiration cytology revealed that they were undifferentiated carcinomas compatible with metastatic lesions from the undifferentiated carcinoma with rhabdoid features from the sigmoid colon. Chemotherapy was administered but was not effective. The patient died 60 days after surgery.

CONCLUSIONS

INI1-negative colorectal undifferentiated carcinomas with rhabdoid features are extremely rare, have high histological malignancy, and a poor prognosis. Chemotherapy is not effective. Effective systemic therapy is desired.

Undifferentiated carcinoma of the transverse colon with rhabdoid features that developed during treatment of non-small cell lung carcinoma with pembrolizumab: a case report

BACKGROUND

Undifferentiated carcinoma of the colon is rare, and its prognosis is very poor. We report a case of undifferentiated carcinoma of the colon with rhabdoid features developed during treatment of non-small lung carcinoma (NSCLC) with pembrolizumab.

CASE PRESENTATION

A 58-year-old man was diagnosed with transverse colon cancer during chemotherapy with pembrolizumab for NSCLC. Laparoscopic right hemicolectomy was performed. The histopathological diagnosis was undifferentiated carcinoma with rhabdoid features and lymph node metastasis. Immunohistochemically, programmed death ligand 1 (PD-L1) showed positivity. The microsatellite instability (MSI) status was low. He continued to receive pembrolizumab for NSCLC, and there have been no signs of colon cancer recurrence and progression of NSCLC for 15 months.

CONCLUSION

We present the case of an undifferentiated carcinoma of the transverse colon with rhabdoid features. The development of the tumor with the expression of PD-L1 during pembrolizumab might have been associated with the low MSI.

BRAF Mutation in Colorectal Rhabdoid and Poorly Differentiated Medullary Carcinomas

Colorectal rhabdoid carcinomas (CRbCs) are very rare and aggressive cancers. The BRAF mutation and CpG island methylator phenotype have been reported to be common features of CRbCs. This study reviews the literature about CRbCs and analyzes the clinicopathological and molecular profiles of seven CRbCs characterized by large discohesive cells with abundant eosinophilic cytoplasm, showing hyaline inclusions and large rounded to bean-shaped nuclei. For comparison, we included four poorly differentiated medullary carcinomas (PDMCs) with focal aspects mimicking rhabdoid features. Overall survival was poor in both subsets, with 78% of patients dying of disease within 2–11 months. The main features of CRbCs were: Loss of/reduced SMARCB1/INI expression, intense vimentin immunostaining, and dense neutrophilic infiltration. The PDMCs were positive for pancytokeratin but negative for vimentin and showed moderate peritumoral/intratumoral CD8+ lymphocytes. All PDMCs showed SMARCB1(INI-1) expression. The coexistence of BRAF and TP53 mutations was observed in 80% of CRbCs and PDMCs. PDMCs always showed microsatellite instability and CpG island methylator phenotype (CIMP), while CRbCs were CIMP negative and exhibited microsatellite instability (MSI) in two out of seven cases. CRbCs are characterized by BRAF and TP53 mutations. Loss/reduced expression of nuclear SMARCB1/INI, intense vimentin immunostaining, dense neutrophilic infiltration, and low frequency of CIMP are useful markers to recognize these rare aggressive tumors.

Extraordinary disease-free survival in a rare malignant extrarenal rhabdoid tumor: a case report and review of the literature

BACKGROUND

Malignant extrarenal rhabdoid tumor of the gastrointestinal tract is rarely reported in the literature. It is characterized by poor prognosis and aggressive metastatic features. A literature review evidenced only 19 cases, with poor outcome.

CASE PRESENTATION

We report a case of a colonic "pure" malignant extrarenal rhabdoid tumor with metastatic nodes in a 65-year-old Caucasian man. He was treated surgically with no recurrence, no adjuvant chemotherapy, and with 4-year survival without disease at the time of the submission of this article.

CONCLUSIONS

We present an extraordinary case of long-term survival due to the extended surgical treatment. We believe that the absence of organ metastasis at presentation is a positive prognostic factor, although pathology confirmed node involvement (13/38 positive) on microscopy.

Rhabdoid carcinoma of the rectum

Rhabdoid colonic tumors are very rare lesions with just a few publications describing such neoplasms. Even more unusual for these lesions are their primary rectal locations, with only two brief case reports having been published on that subject to date. We present a case of a composite rhabdoid rectal carcinoma in a 49-year-old male. The tumor behaved very aggressively, with rapid patient demise despite radical surgery and intensive postoperative chemotherapy (FOLFIRI [folinic acid {leucovorin}, fluorouracil {5-fluorouracil}, and irinotecan] and FOLFOX4 [folinic acid {leucovorin}, fluorouraci {5-fluorouracil}, and oxaliplatin]). Pathologic examination was supportive of a rhabdoid carcinoma, with a compatible immunohistochemical profile, demonstrating synchronous expression of vimentin and epithelial markers in the tumor cells. In addition, BRAF V600E gene mutation, together with a wild-type KRAS gene, was identified, and no evidence of microsatellite instability based on MLH1, MSH2, MSH6, and PMS2 immunophenotypes, i.e., no loss of expression for all 4 markers, was observed. Our reported case confirms previously published observations of the clinical aggressiveness and the poor therapeutic response for rhabdoid tumors.