Subepithelial rectal gastrointestinal stromal tumor – the use of endoscopic ultrasound-guided fine needle aspiration to establish a definitive cytological diagnosis: a case report

Abstract

BackgroundGastrointestinal stromal tumors are the most common mesenchymal neoplasms affecting the gastrointestinal tract. The stomach is the most common location to be affected, and the rectum one of the rarest, but the whole gastrointestinal tract remains susceptible. Gastrointestinal stromal tumors account for only 0.1% of rectal tumors. Currently, endoscopic ultrasound plays an essential role in the diagnostic process of gastrointestinal stromal tumors, especially when the affected sites have a worse outcome and higher morbidity rates.Case presentationWe describe the case of a 68-year-old white Japanese man with a history of long-term mild rectal pain and tenesmus. A digital rectal examination revealed a right palpable solid mass ranging from 3 to 7 cm from his anal verge. A colonoscopy was performed and showed a 5 cm elevated lesion covered by normal mucosa, located 4 cm above the pectineal line. Endoscopic ultrasound confirmed the diagnosis of a homogeneous hypoechoic mass with areas of necrosis as a rectal subepithelial lesion originating at the fourth layer (muscularis propria). He then underwent endoscopic ultrasound-guided fine needle aspiration of the lesion, followed by cytological and immunohistochemistry evaluation. The evaluation showed spindle and epithelioid cells of variable sizes, in fascicles separated by stroma, which reacted firmly and consistently to CD117/c-kit and CD34, and negative to desmin and S-100 protein. There was weak staining for nuclear Ki-67 in the tumor cells. A diagnosis of rectal gastrointestinal stromal tumor was confirmed. After a multidisciplinary meeting, an abdominoperineal resection of his rectum was performed. The pathology of the specimen confirmed the diagnosis of rectal gastrointestinal stromal tumor. He is now asymptomatic after 3 months’ follow-up and is on adjuvant therapy with a tyrosine-kinase inhibitor.ConclusionsGastrointestinal stromal tumors are rare tumors, and among the variety of primary location sites, the rectum is one of the rarest. The localization of this type of tumor has worse outcomes and higher morbidity rates. We report this rare case to emphasize the need for precise diagnosis and the important role of endoscopic ultrasound-guided fine needle aspiration in such situations.

Endoscopic ultrasound fine needle aspiration vs fine needle biopsy in solid lesions: A multi-center analysis

“…However, the diagnostic accuracy of EUS-FNA with cytology is insufficient to verify cellular arrangement and tissue architecture. Procurement of histological samples that yield an adequate amount of tissue suitable for IHC staining is pivotal for personalized management of some lesions, such as metastatic lesions, gastrointestinal stromal tumors, lymphomas, and other uncommon lesions[ 7 , 9 ]. The limitation in achieving diagnosis using EUS-FNA is the pauci-cellular nature of the aspirate with a significant proportion of the collected tissue being distorted or consumed during automated processing and sectioning[ 7 ].…”

“…Tissue architecture and morphology are often difficult to maintain with FNA samples – as a result, typically only providing specimen for cytological analysis. The reduced ability for histologic examination may reduce the diagnostic yield for lesions that require immunohistochemistry, immunophenotyping, or evaluation of histologic architecture such as lymphoma, metastatic lesions, and some subepithelial lesions[ 8 , 9 ]. Inflammatory processes may also adversely affect the diagnostic yield of FNA through associated cellular atypia resulting in false positive cytology[ 1 , 7 , 8 ].…”

Evaluation of endoscopic ultrasound fine-needle aspiration versus fine-needle biopsy and impact of rapid on-site evaluation for pancreatic masses

“…The limitation in achieving diagnosis using EUS-FNA is the pauci-cellular nature of the aspirate with a significant proportion of the collected tissue being distorted or consumed during automated processing and sectioning [17,22]. Procurement of histological samples that yield an adequate amount of tissue suitable for IHC staining is pivotal for personalized management of some lesions, such as metastatic lesions or gastrointestinal stromal tumors (GIST), and other uncommon lesions [12,13,21,22]. In our study, cell-block analysis was possible in 80.41 % of patients after FNA and in 93.42 % after FNB (P < 0.001).…”

“…For example, cytological analysis alone may not distinguish inflammation from well-differentiated neoplasia because inflammation results in a reactive and regenerative process leading to cellular changes. In addition, certain conditions, such as lymphoma, neuroendocrine tumors, autoimmune pancreatitis, and stromal tumors, require histological specimens with preserved architecture, necessitating immunohistochemical (IHC) staining and histologic diagnosis [10][11][12][13]. Furthermore, EUS-FNA often requires multiple passes to obtain adequate tissue and rapid on-site evaluation (ROSE) for optimal yield, although it remains unclear to what extent ROSE impacts diagnostic accuracy [7,14,15].…”

Endoscopic-ultrasound evaluation and fine needle aspiration with a linear echoendoscope in the cecum: it is possible

“…Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) is central to the accurate diagnosis of subepithelial lesions. Similarly, staging of early neoplastic lesions is also an important step in deciding the best treatment option [1,2]. Unfortunately, the oblique endoscopic view of the linear-array echoendoscope precludes routine cecal intubation.…”