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

Malignant rhabdoid tumors (MRTs) are aggressive neoplasms that were first described in young children with renal primary neoplasms [10, 11]. MRTs were later seen to arise at different locations, such as the central nervous system (CNS) [5], liver [6], genitourinary tract [7], and GI tract [8], known with the name of extrarenal rhabdoid tumors (MERTs). The histologic hallmark of MERTs is a centrically located and large nucleus, prominent nucleoli, abundant and eosinophilic cytoplasm, and paranuclear inclusions of intermediate filaments and abundant mitotic figures. Review of the pathologic characteristics of all cases available in the literature demonstrates that centric nuclei are the common feature among all MERTs.

These tumors are described as “composite” when the rhabdoid phenotype is mixed with another type of identifiable neoplasm and termed “pure” when the rhabdoid features are the only identifiable phenotype. When adenocarcinoma and rhabdoid tumor coexist, the rhabdoid features remained similar in all of them [4].

The histogenesis of MERT is unclear. Ota et al. [12] suggested that the rhabdoid tumor cells were derived from a primitive pluripotent cell that had the potential for a wide range of differentiation and accounted for the phenotypic heterogeneity observed in MERTs. In the literature review, we observed that the only patient alive in the “pure” subgroup had no involvement of lymphatic nodes or organ metastasis at the time of surgery, and underwent adjuvant chemotherapy and radiotherapy. In the “composite” subgroup, the patient with a longer survival had positive nodes and received chemotherapy (Table 2). This confirms the difficulty to define a prognosis based on histological findings and the absence of a standard therapeutic protocol, implying the relevance of performing an R0 resection in the first place.

The management of these tumors is usually surgical resection if the tumor is operable. The rare occurrence of MERT has made it complicated to establish adequate survival-improving protocols. Most of the reports indicate that MERTs are highly aggressive tumors, with more than 75% of patients dying within 6 months of the initial diagnosis [3, 4].

GI rhabdoid tumors are very rare. The majority of extrarenal rhabdoid tumors occur in children, while GI rhabdoid tumors are more common in the elderly population. Cytokeratin and vimentin are frequently found on immunochemistry.

Historically, all the rhabdoid colorectal cancers reported in the literature primarily affect older people, with ages ranging from 62 to 84 years of age and with no gender preference. Nevertheless, we found a few cases in young patients in our review.

Recent reviews suggested that these tumors are large and tend to be located in the transverse colon or proximal ascending colon [3, 4], however, our literature review highlighted a predominance in cecum involvement. Surgical tumor resection was adopted by all series as first-line treatment, but despite it, survival remained low with a median survival of 7 months. We noted that patients alive at the time of publication were patients without metastasis at presentation or with limited node involvement. Nevertheless, two of four patients with no macroscopic metastasis or positive nodes during the surgical intervention, expired in less than 2 months. Horazdovsky et al. concluded in their meta-analysis that surgery and actiomycin therapy may improve survival in MERT [13]. Beneficial results of adjuvant treatment have been reported for MERTs in the skin and CNS, but not in the liver. Chemotherapy did not seem to impact survival (Table 1); also, Pancione et al. [6] and Remo et al. [5] reported that adjuvant chemotherapy had no significant benefit. The role of adjuvant treatment for MERT in the gastrointestinal tract is unknown. Since extrarenal rhabdoid tumors are rare, no standard therapeutic pathway exists and no randomized trials that examine the role of chemotherapy combinations or addition of new drugs have been done. Also, the use of radiotherapy did not improve survival in adults with MRTs [14].

We report an extraordinary case of a patient with long-term survival due to the extended surgical treatment. We believe that the absence of organ metastasis at the presentation should be a positive prognostic factor, although pathology confirmed node involvement (13/38 positive) on microscopy. Since we performed an extended right hemicolectomy with lymphadenectomy (upto the main nodes), omentectomy, and removal of the perirenal fat, we believe that the combination of no organ metastasis and careful extended surgery could explain this extraordinary case of long survival. Our Department of Oncology did not propose chemotherapy for our patient due to the absence of a therapeutic protocol with proven efficacy in the literature for this rare tumor. The follow-up CT scans showed absence of disease.