48uep6bbphidcol2|ID
48uep6bbphidvals|1723
48uep6bbph|2000F98CTab_Articles|Fulltext
Glomus tumors are rare tumors of mesenchymal origin. They are composed of modified smooth muscle cells and originate from perivascular glomus bodies.
1 Most are located in the subungual regions. They are rarely found in the gastrointestinal tract where they mostly occur in the stomach.
2 The presentation may vary from non-specific abdominal discomfort to life threatening upper gastrointestinal haemorrhage.
3 Recognition of imaging features helps differentiate this potentially malignant entity from other submucosal tumors.
Case Report
A 35 year old female presented with upper gastrointestinal bleeding. On examination she had pallor and epigastric tenderness. Her blood investigations were unremarkable except for haemoglobin of 7.9gm/dl.
Ultrasound examination revealed a well-defined hypoechoic lesion, in the pre-pyloric region of stomach with a small dimple in the centre of lesion (Figure 1)
Barium meal study showed a well-defined smooth marginated filling defect at the greater curvature in the pre-pyloric region, with obtuse margins and a central dot of barium pooling suggestive of ulceration (Figure 2). CT scan revealed a hypodense, polypoid lesion, measuring 4x3 cm in the pre-pyloric region at the greater curvature. There was enhancement in the arterial phase with persistent progressive enhancement in the portal venous phase (Figure 3). MRI showed a well-defined submucosal T1W hypointense and T2W slightly hyperintense lesion with intense enhancement after gadolinium administration (Figure 4).
Based on the submucosal location, contrast enhancement and central ulceration a provisional diagnosis of gastrointestinal stromal tumor was made with the differentials of carcinoid, haemangioma and glomus tumor.
Anterectomy with Billroth 1 reconstruction was performed. Histopathogy showed that the tumor was arising from the submucosa (Figure 5). There were numerous dilated thin walled vascular channels.Sheets of round to oval tumor cells (glomus cells) containing clear cytoplasm were found. Hemangiopericytoma like areas were seen within the tumor with focal epithelioid differentiation of glomus cells and infrequent mitoses. The serosa was free of tumor. Immunohistochemistry showed that the tumor cells were positive for SMA, vimentin and caldesmon and were negative for synaptophysin, chromogranin, CD 34, CD117. Mib - 1 index was < 1%. Based on these findings a diagnosis of glomus tumor was made.
Discussion
Glomus tumors originate in the neuromyoarterial glomus, a normal arteriovenous shunt abundantly supplied with nerve fibres which has a temperature regulating function.
4 Glomus tumors were first described by Barre and Masson in 1924. They can be found anywhere in the body like bones, joints, skeletal muscles, trachea, kidney, uterus and vagina. The classic location is the subungual region of a digit5 followed by palm, wrist and toes. Rarely they are found in gastrointestinal tract where these commonly occur in the stomach as a solitary submucosal nodule in the pre-pyloric region and less commonly in the small intestine.
2 Glomus tumors are less common than GIST, with a ratio of 1:100.
6 Most of the reported cases are localised to the greater curvature side of the pre-pyloric region of stomach.
Endoscopic ultrasound (EUS) findings suggest that these originate from the third and fourth layer of the stomach based on endoscopic classification.
2,3,7 These lesions may be heterogeneous owing to haemorrhage and calcification, and can be confused with GIST or leiomyosarcoma. On power Doppler sonography, they are hypervascular.
7 On CT, they appear as well-circumscribed submucosal masses and may contain flecks of calcifications. Contrast enhanced study shows intense enhancement in arterial phase persisting in the portal venous phase.
2,3,7 MRI findings, as first described by Kao-Lang Liu in 2005
2 are that the tumor is slightly hypointense on T1-weighted images, slightly hyperintense on T2-weighted images and exhibits persistent enhancement after gadopentetatedimeglumine administration.
Other submucosal enhancing tumors include GIST, schwannomas, ectopic pancreatic rests, haemangiomas, carcinoid tumor, and melanoma metastasis. Pre-operative differentiation of gastric submucosal tumors is important to distinguish them from more malignant counterparts for proper surgical management.
The most common malignant counterpart of a glomus tumor is GIST. However GIST’s more frequently show cystic change with heterogeneous enhancement, ulceration, necrosis, cavitation, and communication with bowel. Mean age of presentation is 40-70 years and the distribution among both the sexes is almost equal. Lymph node metastasis is less common.
2 Definitive diagnosis is possible only on histopathology and immunohistochemistry. Glomus tumors show uniform sized glomus cells located in the walls of dilated vessels with immunoreactivity for smooth muscle actin and calponin, and lack c-KIT(CD 117) mutation (positive in GIST).
7 As gastric glomus tumors have potential malignant behaviour, enucleation is not recommended and wedge resection with negative margins should be the treatment of choice.
7 In case of antral tumors,anterectomy with gastrojejunostomy should be attempted as wedge resection would lead to significant gastric deformity.
References
- Caccamo D, Danedo M, Gordon RE. Glomustumor of the stomach. Mt Sinai J Med. 1987;54:344-347.
- Liu KL, Wang HP, Tseng WY, Shun CT, Chen SJ, Tsang YM. Glomustumorof the stomach: MRI findings. Am J Roentgenol. 2005;185(5):1190-2.
- Huang YC, Chou CT, Hong YC, Ho SY, Lee KW, Wu HK Glomus Tumor of the Stomach. J Radiol Sci. 2011;36:49-53.
- Kim JK, Won JH, Cho YK, Kim MW, Joo HJ, Suh JH. Glomustumor of the stomach: CT findings. Abdom Imaging. 2001;26:303-305.
- Tang M, Hou J, Wu D, Han XY, Zeng MS, Yao XZ. Glomustumor in the stomach: Computed tomography and endoscopic ultrasound findings. World J Gastroenterol. 2013;19(8):1327-1329.
- Miettinen M, Paal E, Lasota J, et al. Gastrointestinal glomustumors. Am J Surg Pathol. 2002;26:301-311.
- Vassiliou I, Tympa A, Theodosopoulos T, Dafnios N, Fragulidis G, Koureas A, Kairi E. Gastric glomus tumor: A case report. World J Surg Oncol. 2010,8:19.