Plexiform Angiomyxoid Myofibroblastic Tumor Research Articles

Plexiform Angiomyxoid Myofibroblastic Tumor: A Rare Mesenchymal Neoplasm

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that was first described in 2007. The tumor is very rare, and to date, only 18 cases confirmed by immunohistochemistry have been reported in the literature. Representative clinical symptoms are ulceration hematemesis, and anemia. The tumors were mostly located at the antrum. Grossly, the tumor is red, white, brown, and forms a lobulated submucosal or transmural mass. Microscopically, the tumor is characterized by a plexiform growth pattern, the proliferation of cytologically bland spindle cells, and a myxoid stroma that is rich in small vessels. Differential diagnoses include gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract. Keywords: Mesenchymal Neoplasm. Read more →

2781 Plexiform Angiomyxoid Myofibroblastic Tumor of the Gastric Cardia: An Uncommon Tumor With an Even Less Common Location

INTRODUCTION: Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a rare gastric tumor of stromal origin with unique immunohistochemical characteristics that differentiate it from other more common gastric stromal tumors. Since its first description in 2007, nearly all have been localized to the gastric antrum. We present a case of a symptomatic PAMT in the gastric cardia successfully treated with resection. CASE DESCRIPTION/METHODS: A 51 year old female complained of left sided abdominal pain, nausea, and early satiety. Esophagogastroduodenoscopy showed a 3 cm endophytic sub-epithelial mass in the posterior wall of the gastric cardia. Follow-up endoscopic ultrasound revealed an 18 mm × 33 mm hypoechoic mass contiguous with the muscularis propria (MP). Biopsies revealed a myxoid lesion composed of bland spindle cells, consistent with a PAMT. The patient was considered for resection given the proximity to the GEJ. Unfortunately, endoscopic management was unsuccessful and the patient subsequently underwent laparoscopic gastric wedge resection sparing the GEJ. Histologic exam revealed bland spindled cells within an eosinophilic fibromyxoid stroma with eosinophilic cytoplasm. While SMA and desmin stains were positive, C-Kit (CD117), DOG-1, and S-100 stains returned negative, confirming a PAMT. The patient’s postoperative course was uneventful at the six week follow-up with resolution of abdominal pain, nausea, and early satiety. DISCUSSION: PAMT is a rare benign tumor most commonly located in the antrum. Although patients are often asymptomatic, ulceration with bleeding, and obstruction are reported. It presents as a submucosal mass ranging from 2 cm – 15 cm. Diagnosis is histological with a nodular to plexiform growth pattern with well-circumscribed islands of spindle cells located within the MP and possible extension into the submucosa with ulceration. The tumor is composed of bland spindled cells separated by loose stroma with myxoid to fibromyxoid material. Cells are indistinct with eosinophilic cytoplasm, bland nuclei with inconspicuous nucleoli. Limited is known about progression of a PAMT but they appear to be slow growing with a good prognosis. Treatment largely consists of surgical resection, although endoscopic mucosal resection has been reported. This case presents a rare location of this rare tumor highlighting the importance of considering it with proximal gastric lesions.

Two Cases of Plexiform Angiomyxoid Myofibroblastic Tumor (PAMT) of Gastrointestinal (GI) Tract: One With 8-Year Follow-up, One in Distal Jejunum

Abstract Objectives PAMT is an exceedingly rare mesenchymal tumor of the gastric antrum that was first described in 2007. Although likely benign, long-term follow-up is limited due to its recent description and rarity. In small bowel, only four cases of PAMT have been reported, two in duodenum and two in proximal jejunum. Methods (A) A 16-year-old female presented with GI bleeding and gastric outlet obstruction. Imaging studies suggested a gastrointestinal stromal tumor (GIST) arising in duodenum. An open biopsy revealed a bland spindle cell neoplasm. Resection of the tumor was performed. (B) A 68-year-old male presented with an incidental mesenteric mass on imaging during hematuria workup. He underwent surgical resection of the mass to exclude a GIST. Results Case A was a 15.0-cm mass arising in gastric antrum, and case B was an 8.0-cm mass arising in antimesenteric side of distal jejunum. Both tumors showed multinodular plexiform growth pattern and foci of cystic changes, with a proliferation of bland spindle cells in a prominent myxoid matrix. Numerous vascular structures were noted without tumor necrosis, nuclear atypia, or mitotic activity. The lesional cells were positive for actin and negative for desmin. The lesional cells were negative for other markers including cytokeratin, CD34, CD117, DOG-1, S-100, and PDGFRA (case B). Both masses were based in the subserosa with focal extension to the muscularis propria in case A. Patient A was followed up for 8 years with no evidence of disease. Patient B was lost to follow-up. Conclusion While clinical presentation and imaging finding of PAMT overlap with GIST, PAMT appears to be more indolent. PAMT of distal jejunum has not been previously reported. Small bowel PAMT is much less common than gastric PAMT but can involve variable segments. PAMT may be underdiagnosed.

Computed tomography and magnetic resonance imaging of a plexiform angiomyxoid myofibroblastic tumor: a case report

BackgroundPlexiform angiomyxoid myofibroblastic tumor (PAMT) is a very rare mesenchymal tumor of the stomach. Here we report a case of pathologically confirmed PAMT with an unique cyst formation.Case presentationA 55-year-old male with a 10-year history of a gastric subepithelial tumor underwent computed tomography (CT) and magnetic resonance imaging (MRI). Two cysts were observed in the tumor, and the cyst wall showed moderately high intensity on T2-weighted images compared with the gastric wall. On dynamic study, the cyst wall showed a gradual enhancement pattern, and prominent enhancement was observed in the delayed phase. Laparoscopic partial gastric resection was performed, and a pathological diagnosis of PAMT was rendered.ConclusionWe present a rare case of gastric PAMT, which was uniquely presented as cysts. One of the cysts in the tumor had an epithelial wall lining, which had never been reported before in gastric mesenchymal tumor, in addition to partial glandular structure. We reviewed our case, focusing on radiologic-pathologic correlation, and suggested hypothesis of cyst formation. According to our findings, PAMT with cyst formation would be included of differential diagnosis of gastric subepithelial tumors.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach: Report of a Case and Review of the Literature

We report a case of a plexiform angiomyxoid myofibroblastic tumor of the stomach that developed in a 38-year-old woman who underwent gastrofiberscopy and multi-detector computed tomography scans due to dyspepsia for 3 months. There was a subepithelial protruding mass with a small central mucosal ulceration and heterogeneous prominent enhancement in the gastric upper body along the greater curvature. The tumor measured 3.5 × 2.3 cm in size and showed a multinodular plexiform growth pattern of bland spindle cells in the myxoid stroma with abundant small blood vessels. The tumor cells were negative for CD117 (c-KIT), CD34, and S-100 protein but diffusely positive for smooth muscle actin and Alcian blue. The pathologic examination demonstrated that the lesion was a plexiform angiomyxoid myofibroblastic tumor. The patient is doing well and has had no recurrence or metastasis for 6 months after the wedge resection.

Plexiform Fibromyxoma (Plexiform Angiomyxoid Myofibroblastic Tumor) of Stomach

Plexiform fibromyxoma (plexiform angiomyxoid myofibroblastic tumor) is a rare benign mesenchymal tumor of stomach. The plexiform growth of bland-looking spindly cells in a richly vascularized fibromyxoid stroma is distinctive. The described cases are solid tumors associated with ulceration, with the patients presenting with symptoms related to the ulcer or mass effect of the tumor. We report an unusual case presenting as a fistulating abscess. A 42-year-old woman presented with abdominal pain, fever, and elevated white cell count. Computed tomography scan revealed a 12-cm cavitating mass in the gastric antrum, with fistulation to the gastric lumen through an ulcer. Histologic examination showed transmural involvement of the stomach by plexiform islands of fibromyxoid tumor with interspersed delicate capillaries. There was a pseudocyst-like component. The unusual presentation therefore broadens the clinical and pathologic spectrum of this rare tumor type.

Plexiform angiomyxoid myofibroblastic tumor of stomach

To study the clinicopathologic features, immunophenotype and differential diagnosis of plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach. The clinical and pathologic findings of 3 cases of PAMT in the gastric antrum were retrospectively analyzed. Immunohistochemical study was carried out and the literature was reviewed. The age of patients ranged from 31 to 47 years. The male-to-female ratio was 1:2. The clinical presentation included epigastric pain and distension. Endoscopically, the tumor mass protruded into the gastric cavity at the antrum and ranged from 4.5 cm to 8.0 cm in greatest dimension. One of the tumors studied was associated with surface ulceration. Histologically, the tumors were located in the gastric wall. They were composed of bland spindle cells and small vessels arranged in a plexiform or nodular pattern within a myxoid stroma. Immunohistochemical study showed that the spindle cells were consistently positive for smooth muscle actin and muscle-specific actin. There was focal staining for h-caldesmon, desmin in case 3 and focal positive for epithelial membrane antigen, CAM5.2 in case 1. Further, CD10 and progesterone receptor were positive in case 3. PAMT represents a rare novel mesenchymal tumor of the stomach, with a propensity of gastric antral involvement. The distinctive pathologic features help to differentiate this entity from other benign and malignant tumors.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described gastric tumor with a peculiar plexiform pattern, bland spindle cells and a myxoid stroma rich in arborizing blood vessels. PAMT of the stomach is a very rare tumor without distinctive clinical manifestations. In this study, we report a new case of PAMT which is the first Chinese case in English literature. A 47-year-old Chinese woman was admitted with a 6-month history of intermittent epigastric discomfort, and abdominal pain for 2 months. Gastroscopy showed an elevated mass in the anterior wall of the gastric antrum. Endoscopic ultrasound revealed a focal hypoechoic lesion protruding into the lumen. A laparoscopic distal gastrectomy was performed, and the patient made an uneventful recovery and remains well 1.5 years later. A diagnosis of PAMT was made by histopathology and immunochemistry.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach: Report of Two Cases and Review of the Literature

Plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach is a recently recognized entity. Because of its rarity, only 22 cases have been reported in the English-language literature and most of these are single case reports. We report two cases of gastric PAMT. The tumor cells were bland and plexiform arranged in a myxoid stroma, which was positive for alcian blue. Immunohistochemically, the tumor cells were positive for smooth muscle actin, but negative for c-kit, CD34, desmin, S-100 protein, epithelial membrane antigen, neurofilament, and protein kinase C-theta. Mutation analyses for exon 9, 11, 13, and 17 of KIT genes and 12, 14, and 18 of the platelet-derived growth factor receptor alpha (PDGFRA) genes were performed and the tumors were wild-type for mutation.

Selected Unusual Tumors of the Stomach

Several unusual stomach tumors have been recently described. In addition, some tumors that are often encountered in other sites may rarely occur as primary gastric tumors. The diagnostic surgical pathologist needs to be aware of some of these lesions to prevent misdiagnosis. This overview discusses the key clinical features, pathology, immunohistochemistry, and relevant molecular findings of multiple minute gastrointestinal stromal tumors and interstitial cell of Cajal hyperplasia, nerve sheath tumors (schwannoma and perineurioma), gastroblastoma, granular cell tumor, glomus tumor, plexiform angiomyxoid myofibroblastic tumor, and primary clear cell sarcoma of the gastrointestinal tract that occur as primary gastric neoplasms.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach: A Case Report

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described mesenchymal tumor of the stomach. We report the first case of PAMT in Korea. A 52-yr-old man underwent esophagogastroduodenoscopy due to dyspepsia for 2 yr. There was a submucosal mass with small mucosal ulceration in the gastric antrum. The tumor measured 3.5 × 2.3 cm in size and showed multinodular plexiform growth pattern of bland-looking spindle cells separated by an abundant myxoid or fibromyxoid matrix rich in small thin-walled blood vessels. The tumor cells were negative for CD117 (c-KIT), CD34 and S-100 protein, but diffusely positive for smooth muscle actin consistent with predominant myofibroblastic differentiation. The patient is doing well without recurrence or metastasis for 5 months after surgery. Although there have been limited follow-up data, PAMT is regarded as a benign gastric neoplasm with histological and immunohistochemical charateristics distinguished from gastrointestinal stromal tumor and other mesenchymal tumors of the stomach.

Gastric plexiform angiomyxoid myofibroblastic tumor

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a relatively recently described gastric tumor with a peculiar plexiform growth pattern. PAMT is typified by a myofibroblastic immunophenotype that distinguishes it from the more common gastrointestinal stromal tumors and the rarely documented fibromyxomas. We report an additional PAMT, the seventh tumor with this label, which was an incidental finding on abdominal computed tomography scan of a 35-year-old Indian female. The tumor measured 4 x 3 x 2 cm and demonstrated plexiform architecture, myxoid stroma, prominent vasculature and spindled cells with myofibroblastic differentiation. The clinicopathological features, progesterone immunopositivity, hitherto undocumented, and mimicry of other primary and secondary gastric mesenchymal tumors, including endometrial stromal sarcoma, are discussed.

Plexiform angiomyxoid myofibroblastic tumor of the stomach

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that we first described in 2007. The tumor is very rare, and to date, only 18 cases confirmed by immunohistochemistry have been reported in the literature. The patients' ages ranged from 7 to 75 years (mean, 43 years), and the male-to-female ratio was approximately 1:1. Representative clinical symptoms are ulceration, associated upper gastrointestinal bleeding (hematemesis), and anemia. The tumors are located at the antrum in all cases, and grossly, the tumor is whitish to brownish or reddish, and forms a lobulated submucosal or transmural mass. Microscopically, the tumor is characterized by a plexiform growth pattern, the proliferation of cytologically bland spindle cells, and a myxoid stroma that is rich in small vessels and positive for Alcian blue stain. Immunohistochemically, the tumor cells are positive for alpha-smooth muscle actin and negative for KIT and CD34. Differential diagnoses include gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract. Some authors proposed that this tumor should be designated as "plexiform fibromyxoma", but this designation might cause confusion. The tumor is probably benign and thus far, neither recurrence nor metastasis has been reported.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that we first described in 2007.The tumor is very rare,and to date,only 18 cases confirmed by immunohistochemistry have been reported in the literature.The patients' ages ranged from 7 to 75 years(mean,43 years),and the male-to-female ratio was approximately 1:1.Representative clinical symptoms are ulceration,associated upper gastrointestinal bleeding(hematemesis),and anemia.The tumors are located at the antrum in all c...

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach

We report 2 cases of plexiform angiomyxoid myofibroblastic tumor of the stomach, a tumor entity that has not been described previously. The patients were a 50-year-old man (case 1) and a 68-year-old man (case 2). In case 1, the patient presented with acute abdominal pain. The tumor in case 2 was incidentally found at laparoscopic cholecystectomy. Grossly, the tumors were 4.0 cm (case 1) and 4.5 cm (case 2) in their greatest dimension, and they were recognized as submucosal tumors. The tumor caused gastric perforation in case 1. Histologically, the tumors extended from the serosa to the submucosa of the gastric wall, showing a plexiform growth pattern. Bland spindle tumor cells were observed, and they were separated by abundant intercellular myxoid matrix. The stroma was rich in small vessels. Immunohistochemically, the tumor cells were positive for alpha-smooth muscle actin and muscle actin, and negative for KIT, CD34, and S-100 protein. Electron microscopic findings were consistent with the myofibroblastic nature of the tumor cells. No mutations were found in the c-kit and platelet-derived growth factor receptor alpha genes. Although clinical follow-up data were insufficient, the histologic appearances suggested the benign nature of the tumors. However, the tumor in case 1 caused gastric perforation and necessitated an emergency operation.