Malignant Gastrointestinal Stromal Tumor of Rectum: A Case Report and Review of Literature

Adjuvant therapy for rare rectal gastrointestinal stromal tumors: A case report

Key Clinical Message

Anorectal gastrointestinal stromal tumors are extremely rare, constituting less than 0.1% of rectal tumors. Surgical resection using a transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors can be a successful treatment combination to remove the mass and prevent recurrence while preserving the integrity of the anal sphincter.

Abstract

Gastrointestinal stromal tumors (GISTs) are a rare subset of neoplasms, accounting for about 1%-2% of primary gastrointestinal malignancies. The stomach is the most common site for GISTs, with anorectal GISTs being exceptionally rare, representing only 0.1% of all rectal tumors. The standard approach for managing localized GIST involves complete surgical excision to achieve negative microscopic margins (R0) while preserving the tumor capsule and maintaining anal sphincter function. Surgical resection with transanal wide excision followed by adjuvant therapy using tyrosine kinase inhibitors can successfully remove the mass, prevent recurrence, and preserve the anal sphincter's integrity. Adjuvant therapy with imatinib is the recommended treatment for all localized GISTs assessed to have an intermediate or high risk of relapse. Here, we report a case of a 63-year-old male with a rectal GIST who underwent transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors.

Malignant rectal GIST managed with chemotherapy (Imatinib Mesylate): A case report and a comprehensive review

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors involving the gastrointestinal tract, arising from the interstitial cells of Cajal. GIST comprises about 1% of all GI tumors. Rectal GISTs are rare and comprise of approximately 5% of all GISTs and only 0.1% of rectal tumors are found to be GISTs. Rectal GISTs may be diagnosed incidentally or present with symptoms, including defecation problems, bleeding, and/or pain. We report a case of a 46-year-old male with rectal GIST metastasized to the liver and bilateral lung parenchyma managed by Imatinib Mesylate (IM) regimen. Rectal GIST although being rare, must be considered as a differential diagnosis in a patient presenting with defecatory problems with bleeding.

Concurrence of Adenomyoepithelioma of the Breast and Gastrointestinal Stromal Tumor of the Stomach: A Case Report and Review of the Literature

Adenomyoepithelioma (AME) of the breast and gastrointestinal stromal tumors (GISTs) are rare benign (primarily) tumors observed in the breast and gastrointestinal tract, respectively. The coexistence of both of these rare tumors is extremely rare; therefore, the author describes the clinical presentation and pathophysiological findings of such a unique case in this study. A 56-year-old female patient with no medical history presented with a substantial right breast lump, severe nausea, and vomiting, and suffered from iron deficiency anemia. Radiological observation and a right breast excisional biopsy diagnosed the patient with AME associated with ductal carcinoma in situ (DCIS). Endoscopy and a CT scan of the stomach revealed the existence of GIST. This is the first reported case of concurrence of a huge mass of AME and GIST in a patient. Histological and immunohistochemistry tests using p63, SMA, calponin, and Ki67 markers for the breast tumor and DOG-1, CD34, and CD117 markers for the gastric tumor revealed the non-invasive benign state. The patient had a right breast mastectomy with a negative resection margin. AME of the breast and GIST pose diagnostic challenges due to their erratic morphological characteristics and can cause misinterpretation drawn solely from radiological tests. Effective and accurate diagnostics require assessing the histological and immunohistochemistry findings of the tumor to identify the invasiveness of the neoplasm and the associated risk levels. This report, thus, creates awareness among clinicians and pathologists for the consideration of such possibilities and, therefore, conducts the necessary diagnostics and prophylactic treatments.

A Rare Case of a Rectal Gastrointestinal Stromal Tumor (GIST) Discovered During a Routine Colonoscopy

A gastrointestinal stromal tumor (GIST) is a rare malignancy, accounting for only 0.1% to 3% of all gastrointestinal (GI) malignancies. Although GISTs are the most common mesenchymal tumor of the GI tract, they are primarily found within the stomach, with rectal GISTs rarely reported. They may present with rectal bleeding, constipation, pain, or a palpable mass while some are found incidentally. The incidence of GISTs has been on the rise, possibly due to advancements in diagnostic technology. In this case report, we present a 50-year-old female who presented with intermittent constipation and rectal pain and was found to have a submucosal rectal mass during a routine diagnostic colonoscopy. Further evaluation confirmed the presence of a spindle-cell neoplasm, which was mildly cellular and showed positive expression of CD34 and CD117 on immunohistochemistry, consistent with the diagnosis of GIST of the rectum. This case report emphasizes the importance of routine colonoscopies in the early detection of neoplastic lesions of the colon and highlights the rare incidence of GISTs, their risk factors, pathogenesis, and common sites of occurrence.

Anal canal gastrointestinal stromal tumour (GIST)

SummaryGastrointestinal stromal tumours (GISTs) are malignant mesenchymal tumours that originate from the interstitial pacemaker cells of Cajal. They are particularly rare, comprising only 5% of all GISTs, and often present at an advanced stage. Treatment for these tumours is still a topic of debate due to their low incidence and insidious location. A woman in her mid-70s presented with rectal bleeding and anal discomfort. A 4.5×4 cm anal GIST was diagnosed. A local excision was performed and the patient was further treated with tyrosine kinase inhibitors. At a 6-month follow-up, the MRI showed that she was disease free. Anorectal GISTs are unusual and tend to be aggressive. Surgical resection is the first-line treatment for primary, localised GISTs. However, the appropriate surgical technique for these tumours is still a topic of debate. Further studies are needed to fully understand the oncologic behaviour of these rare neoplasms.

A rectal gastrointestinal stromal tumor case accompanied by elevated CEA mimicking rectal carcinoma on 18F-FDG PET/CT

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm arising from gastrointestinal tract and can be benign or malignant. Rectal GISTs are rare and have poor prognosis. We here reported an older male who presented with features of distending discomfort in the rectum and pain in the anus due to a large rectal tumor. Physical examinations detected a mass in the rectum without blood staining on the gloved finger. Carcinoembryonic antigen (CEA) was found to be slightly elevated and the prostate-specific antigen level was normal. ¹⁸F-FDG PET/CT showed a soft tissue density mass at the bottom of the pelvic, with an unclear boundary to the surroundings with the significantly increased FDG uptake (SUVmax 17.5). Although a rectal carcinoma was suspected based on the finding of PET/CT and CEA, the histopathological examination confirmed the diagnosis of the malignant GIST of the rectum. The patient was then treated with imatinib and on follow-up regularly. In this case, ¹⁸F-FDG PET/CT shows the advantage of visualizing both primary and metastatic lesions and provides valuable information for the diagnosis, staging, evaluation, and prognosis of GIST.