Gastric leiomyosarcoma and diagnostic pitfalls: a case report

Abstract

BackgroundSince the advent of immunohistochemistry for the diagnosis of stromal tumours, the incidence of leiomyosarcomas has significantly decreased. Nowadays, gastric leiomyosarcoma is an exceptionally rare tumour. We report the second case in the English literature of gastric leiomyosarcoma revealed with massive bleeding and hemodynamic instability and diagnostic pitfalls that we encountered.Case presentationA 63-year-old woman, with 2 years’ history of dizziness and weakness probably related to an anaemic syndrome, presented to the emergency room with hematemesis, melena and hemodynamic instability.On examination, she had conjunctival pallor with reduced general condition, blood pressure of 90/45 mmHg and a pulse between 110 and 120 beats per minute. On digital rectal examination, she had melena. Laboratory blood tests revealed a haemoglobin level at 38 g/L.The patient was admitted to the intensive care department. After initial resuscitation, transfusion and intravenous Omeprazole continuous infusion, her condition was stabilized. She underwent upper gastrointestinal endoscopy showing a tumour of the cardia, protruding in the lumen with mucosal ulceration and clots in the stomach. Biopsies were taken. Histological examination showed interlacing bundles of spindle cells, ill-defined cell borders, elongated hyperchromatic nuclei with marked pleomorphism and paranuclear vacuolization. Immunohistochemistry showed positivity for Vimentine, a strong and diffuse immunoreactivity for smooth muscle actin (SMA). Immunoreactivities for KIT and DOG1 were doubtful.Computed tomography scan revealed a seven-cm tumour of the cardia, without adenopathy or liver metastasis.The patient underwent laparotomy. A total gastrectomy was performed without lymphadenectomy. Post-operative course was uneventful.Histological examination of the tumour specimen found the same features as preoperative biopsies with negative margins. We solicited a second opinion of an expert in a reference centre for sarcomas in France, who confirmed the diagnosis of a high grade gastric leiomyosarcoma.ConclusionGastric leiomyosarcoma is a rare tumour. Diagnosis is based on histological examination with immunohistochemistry, which could be sometimes confusing like in our case. The validation of a pathological expert is recommended.

Leiomyosarcoma of the stomach: A case report

“…Before the advent of KIT immunohistochemistry, GISTs were misdiagnosed as leiomyomas and leiomyosarcomas. Since the establishment of KIT immunohistochemistry in the late 1990s, we have realized that primary gastric leiomyosarcoma is extremely rare and reportedly accounts for fewer than 1% of gastric tumors[1,2]. Only 13 well-described cases have been reported in English language literature since 2007[1-13] (Table 2).…”

“…The diameters of the tumors described in the literature vary from 1 to 18 cm[1-13]. The origin of gastric leiomyosarcoma is usually between the muscularis propria and muscularis mucosa layers[2]. Agaimy et al[15] reported 85 cases of true smooth muscle neoplasms of the gastrointestinal tract and found that only one case of polypoid leiomyosarcoma arose from the muscularis mucosae of the stomach.…”

“…In general, SMA, desmin, and h-caldesmon are positive in the majority (≥ 70%) of leiomyosarcoma cases[14], and CD117 ( KIT ), DOG1 and CD 34 are negative. DOG1 is the best marker for GIST, and there have been no gastric leiomyosarcoma cases with positive DOG1 staining[2]. Considering that 10% of GISTs are KIT -negative, gene analysis of KIT or PDGFRA leads to a conclusive diagnosis of gastric leiomyosarcoma.…”

“…It is difficult to make a precise judgement with endoscopy, and its diagnostic value is unclear. However, endoscopic ultrasonography is very sensitive, with a success rate of up to 97%[16] in the diagnosis of leiomyosarcoma of the stomach[2]. With the guidance of endoscopic ultrasonography, biopsy may be possible, and a histological examination can be performed.…”

A case of laparoscopic resection of leiomyosarcoma arising in the mesentery of descending colon: a case report and review of the literature

“…Leiomyosarcoma (LMS) is a rare malignant tumor that originates from smooth muscle cells 1 . It was reported to occur in any smooth muscle cell‐containing organ, such as the uterus: stomach: intestine: retroperitoneum: and blood vessels such as the portal vein and inferior vena cava 2‐7 . On the other hand, a mesenteric origin of LMS is extremely rare, with a small number of reported cases 8 .…”