Granular Cell Tumor Research Articles

S1867 Rectal and Esophageal Granular Cell Tumors; A Report of Two Cases

Introduction: Granular cell tumors (GCT) are a predominantly benign tumor arising from mesenchymal origin - specifically Schwann cells. They typically appear as a solitary mass; in the gastrointestinal tract (GIT), they can present as a painless yellow-gray polyp or nodule. It is more commonly found in women ages 10-50 years old. They can arise in any location, most commonly from the skin, and only 10% found in the GIT. Within the GIT, the esophagus is the most common location while the rectum is the rarest location. Case description/methods: Case #1: Patient is a 51-year-old female with no significant past medical history coming in with right upper quadrant (RUQ) abdominal pain. Pain has been present for 1 month prior to seeking medical attention. Pain is not consistently associated with eating food. There is no associated nausea, vomiting, diarrhea, or constipation. EGD was performed at that time and revealed a white localized plaque (image 1A). Histopathology on H&E stain revealed esophageal mucosa with underlying sheets of epithelioid cells with abundant granular eosinophilic cytoplasm (image 1B). S100 stain was positive, but MART1 and SOX10 were negative. Case #2: Patient is a 64-year-old male with a past medical history significant for aortic stenosis who presented for his first screening colonoscopy. At that time, colonoscopy revealed mild erythematous mucosa in the terminal ileum and sigmoid colon as well as a small mass in the rectum (image 1C). Biopsy results revealed focal active colitis in the sigmoid colon and a rectal granular cell tumor in the rectum. Histopathology of the tumor revealed colorectal mucosa with packets of uniform epithelioid cells with abundant eosinophilic granular cytoplasm interdigitating with the colonic crypts on H&E stains (Image 1D). S100 immunohistochemistry stain demonstrated diffuse expression within the granular cell tumor with absent staining in crypt epithelium (Image 1E-F). MART1 and SOX10 were negative as well. Discussion: GCTs are rare tumors ad account for 0.5% of all soft tissue tumors. Only 10% occur in the GIT and rarely in the rectum. Most are benign with only 1-2% being malignant. If ulceration is found, malignancy should be ruled out. It is also important to differentiate them from other tumor occurring in the GIT such as neurogenic and gastrointestinal stromal tumors. It is also important to differentiate them from melanomas as they stain positive for S100; melanoma specific stains, such as MART1 and SOX10, are used to differentiate them.Figure 1.: (A) White localized plaque in the esophagus. (B) Esophageal mucosa with underlying sheets of epithelioid cells with abundant granular eosinophilic cytoplasm. (C) Small yellowish mass in the rectum. (D) H&E stain revealing colorectal mucosa with packets of uniform epithelioid cells with abundant eosinophilic granular cytoplasm interdigitating with the colonic crypts. (E) S100 immunohistochemistry stain demonstrating diffuse expression within the granular cell tumor with absent staining in crypt epithelium. (F) Rectal granular cell tumor negative for MART1 and SOX10 at 20x magnification.

MULTIFOCAL PULMONARY GRANULAR CELL TUMOR

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Granular cell tumors, also known as Abrikossoff tumors, are a rare group of Schwannian neoplasms typically found in the skin and tongue, but also occur in the lung. Granularity of the cells is due to accumulation of secondary lysosomes in the cytoplasm. Only 0.5-2% of pulmonary granular cell tumors (pGCT) are malignant, but some benign cases show similar behavior. Here, we describe a diagnostically challenging case of multifocal pGCT. CASE PRESENTATION: A 48-year old male with history of asthma, chronic obstructive pulmonary disease, hypertension, and alcoholic steatohepatitis presented for evaluation of a right lung mass found on chest X-ray 5 years ago. He endorsed progressive dyspnea poorly controlled with beclomethasone and albuterol inhalers. He had history of tobacco smoking with 31 pack-years, as well as alcohol abuse. He worked in a shipyard for 3 years with exposure to asbestos and welding fumes. Computed tomography of the chest showed a 4.1-cm solid mass in the right lower lobe, as well as a 1.1-cm endobronchial lesion in the right bronchus intermedius, multiple left lower lobe lesions, and mediastinal lymphadenopathy. Spirometry showed moderate obstructive disease with bronchodilator response. Biopsies of lower lobe and tracheal mucosal lesions obtained by bronchoscopy revealed sheets of epithelioid cells with abundant eosinophilic granular cytoplasm and small uniform nuclei consistent with pGCT. There was no evidence of necrosis or increased mitotic figures to suggest malignancy. Immunostaining was positive for S100, CD68, SOX10, inhibin, and PAS. He was referred to Interventional Pulmonology for laser debulking and endobronchial stenting. DISCUSSION: Determining whether pGCTs are malignant or benign can be challenging. Both types occur in all age groups. Both can cause dyspnea, cough, and pleuritic chest pain. Large tumor size is not predictive, as many malignant pGCT's are <4 cm at time of diagnosis. Additionally, 20% of benign pGCTs have multiple lung lesions. However, the presence of extrapulmonary metastases is diagnostic of malignancy. Malignant pGCTs also show 3 or more histologic features of the Fanburg-Smith criteria, including necrosis, spindling, pleomorphism, vesicular nuclei with large nucleoli, high nuclear/cytoplasmic ratio, and increased mitotic activity. Positive p53 or Ki67 immunostaining can indicate malignancy in indeterminate cases. Management of benign pGCTs is surgical. Small tumors <1.0 cm may be removed by bronchoscopic extirpation, laser therapy, or sleeve resection. Larger tumors are resected surgically. Prognosis for benign pGCT is good (2-8% recurrence) if complete margin-free removal is achieved. CONCLUSIONS: Malignant and benign pGCTs share many features that make them difficult to differentiate. Absence of extrapulmonary metastases, Fanburg-Smith criteria, and specific immunostaining helps rule out malignancy in cases with multifocal lung lesions. REFERENCE #1: Jiang M, Anderson T, Nwogu C, Tan D. Pulmonary malignant granular cell tumor. World J Surg Oncol. 2003;1(1):22. Published 2003 Oct 21. doi:10.1186/1477-7819-1-22. REFERENCE #2: Fanburg-Smith JC, Meis-Kindblom JM, Fante R, Kindblom LG. Malignant granular cell tumor of soft tissue. Diagnostic criteria and clinicopathologic correlation. Am J Surg Pathol. 1998;22:779–794. doi: 10.1097/00000478-199807000-00001. REFERENCE #3: Khansur T, Balducci L, Tavassoli M. Granular cell tumor: clinical spectrum of the benign and malignant entity. Cancer. 1987;60:220–222. DISCLOSURES: No relevant relationships by Ramiz Fargo, source=Web Response No relevant relationships by Joseph Mak, source=Admin input No relevant relationships by Bryce Mikel, source=Web Response

Use of uniportal video-assisted thoracic surgery combined with a posterior approach to resect a dumbbell-shaped mediastinal granular cell tumor: A case report.

IntroductionA dumbbell-shaped mediastinal granular cell tumor has never been reported, and there have been no reports of dumbbell-shaped tumors resected with a combination of uniportal video-assisted thoracic surgery and the posterior approach.Presentation of caseAn 18-year-old woman was diagnosed with a mediastinal dumbbell-shaped granular cell tumor by computed tomography. Complete resection was achieved via a posterior approach combined with the uniportal video-assisted thoracic surgery. First, a T3 left hemilaminectomy was performed in the prone position and the tumor located inside the intervertebral foramen was removed as far as possible. Next, the patient was repositioned to the right lateral decubitus position, a 2.5-cm skin incision was made on the 4th intercostal posterior axillary line, and resection of the residual tumor was performed. Pathological diagnosis of the resected tumor revealed a benign granular cell tumor. The patient recovered post-surgery and no tumor was reported in the 4-month follow-up magnetic resonance imaging.DiscussionThis is the first reported case of a mediastinal dumbbell-shaped granular cell tumor and its successful resection using a combined posterior and uniportal video-assisted thoracic surgery approach.ConclusionThis is a potentially safe and effective procedure for mediastinal granular cell tumors, with outstanding cosmetic advantages.

S2114 IgG4-Related Disease: An Uncommon Location

Introduction: Granular cell tumors (GCTs) of the esophagus are rare and benign neoplasms of neural cell origin. The lesions are often incidentally identified during upper endoscopic evaluation for other indications. We report a case of esophageal GCT in a young patient who presented with heartburn. Case Description/Methods: A 29-year-old white woman with a history of bulimia nervosa, gastroesophageal reflux disease, and chronic diarrhea following a recent COVID-19 infection presented to the clinic with heartburn and regurgitation that had been ongoing for years. She recently switched her omeprazole to famotidine to prepare for conception, which made her symptoms worse. Her physical examination and laboratory investigations were unremarkable. Esophagogastroduodenoscopy showed a single 6 mm yellowish, firm, submucosal nodule in the distal esophagus (Fig. 1A) and chronic gastritis. The nodule was biopsied with cold forceps and proved to be a granular cell tumor (Fig. 1B). The granular cell tumor cells were negative for pan-cytokeratin and positive for S100 (Fig 1C). They were negative for CD45 and Synaptophysin by immunohistochemistry staining. Biopsy of the distal esophagus also confirmed a short segment of Barrett's esophagus without dysplasia. Gastric body and antrum biopsy showed mild chronic gastritis negative for Helicobacter pylori. She was scheduled for an endoscopic ultrasound followed by possible endoscopic mucosal resection. Discussion: Even though esophageal GCTs are benign incidental findings, they have malignant potential (1-4%). Mortality is related to the size, growth, and invasiveness of the tumor. Indications for endoscopic or surgical resection are large size ≥ 1 cm, rapid growth, high suspicion of malignancy, transmural infiltration, and persistent symptoms. Endoscopic resection techniques include endoscopic mucosal resection and submucosal tunnel endoscopic resection. The later is more preferred in lesions < 3 cm. One study reported no recurrence of esophageal GCTs after resection in 14 cases at a median of 4-year follow-up.

Granular cell tumor in the maxillary mucosa

Granular cell tumor in the maxillary mucosa

S2220 A Rare Case of Intramucosal Neuroma

Introduction: Mucosal Neuromas are rarely found in the colon. They appear as ill-defined polyps and are made of hyperplastic nerve fibers arranged irregularly. We present a rare case of intramucosal neuroma with isolated involvement of the transverse colon which is extremely rare. Case Description/Methods: A 55 years old African American female with a past medical history of Diabetes Mellitus presented for the average risk screening colonoscopy. The patient denied any previous screening procedures. Also denied any high-risk signs and symptoms including weight loss, hematochezia, altered bowel habits. The patient did not have any personal or family history of malignancy. The patient underwent her colonoscopy and was found to have one 8mm polyp in the transverse colon which was removed using a cold snare polypectomy. The rest of the examination looked well including the retroflexion. The pathology results showed intramucosal colonic neuroma. The results were reviewed with the pathologist and discussed with the patient with conservative follow-up. Discussion: Benign tumors of the nerve sheath are common in skin and soft tissues although involvement of the gastrointestinal tract is very rare. Neural masses in the colon can present as masses such as schwannomas or small colorectal polyp. These polyps include neuroma, granular cell tumor and ganglioneuromas. In recent years, intramucosal neural proliferation is also seen in the colon and appears as polyps at the time of endoscopy. These lesions lack ganglion cells and are referred to as neuromas although the presence of ganglion cells is characteristic for ganglioneuroma. However, these polyps are not known to be associated with NF1 or other inherited syndromes. (1) It is important to differentiate neuromas from GIST, which has characteristic immunoreactivity to C-Kit and CD-117. Our patient was found to be positive for S-100 protein and CD-117 negative. Table 1 is a brief literature review of unusual polyps found in the colon.Table 1.: GIST: Gastrointestinal Stromal Tumor, MEN-2B: Multiple Endocrine Neoplasia-2, NF-1: Neurofibromatosis 1, MSCH: Mucosal Schwann Cell HamartomaFigure 1.: Demonstration video: please scan the QR code with your mobile phone camera and click the link.

S3149 Plexiform Fibromyxoma: A Perplexing Condition of the Stomach

Introduction: Plexiform fibromyxoma (PF) is a rare, often benign tumor of mesenchymal origin typically found within the stomach. It features a plexiform cellular architecture of myofibroblasts encircled by a myxoid intercellular matrix with rich vasculature. Takahashi et. al described the first cases of known PF in 2007. It was officially recognized as a subtype of gastric mesenchymal neoplasm by the World Health Organization in 2010. Here, we present a case of PF detected during surveillance endoscopy. Case Description/Methods: 64-year-old male presented for esophagogastroduodenoscopy (EGD) with ablation of Barrett esophagus with low-grade dysplasia. He had undergone 4 previous EGDs remarkable for hyperplastic antral polyps which were removed. His most recent physical exam and labs were unremarkable. During the EGD, he was found to have antral erythema with no clear discernable lesions (figure 1). Biopsies of the region were obtained which stained negative for cytokeratin AE1/AE3, S100, CKIT/CD34 (in lesional cells), and DOG1 while positive for smooth muscle actin (SMA), consistent with PF. Discussion: The clinical presentation of PF is usually nonspecific. Commonly reported symptoms include abdominal pain, fullness, nausea, and vomiting, followed by complications of symptomatic anemia such as syncope. Reported size of PF lesions range from 0.8 - 17.0 cm. Immunohistochemically, the tumor cells are positive for SMA and vimentin, and can show focal or partial staining for CD10, desmin and caldesmon. The spindle cells are negative for DOG-1, C-KIT, epithelial membrane antigen (EMA), ALK, S-100 and CD34 with a low Ki-67 proliferation index. On CT or MRI imaging, PF appears as a solid, cystic, or solid/cystic mass with well-defined borders. Due to the increased vascularity of the tumor, CT with contrast may show mild enhancement of the solid portion during the arterial phase and strengthened progressive enhancement during the venous and delayed phases. Differential diagnoses for these tumors include gastrointestinal stromal tumors (GIST), leiomyoma, granular cell tumor, schwannoma, myxoma and angiomyxoma, gastric blastoma and malignant epithelioid tumor with GLI1 rearrangement. The current treatment of choice is surgical excision. Given the lack of clear lesion in our patient, further imaging will be obtained to attempt to determine margins. Increased awareness by endoscopists and pathologists of this condition is necessary for accurate diagnosis and management of this condition.Figure 1.: Endoscopic visualization of pre-pyloric ulcers.

S1777 Polyps and an Uninvited Host

Introduction: Blood fluke illness like Schistosomiasis is considered rare in the United States. Most cases are reported in patients that have migrated from endemic zones like Africa or Asia. Occasionally this infection is seen in individuals from non-endemic regions whereby travel history plays an important role in diagnosis. Zoonotic diseases can be life threatening, thus prompt treatment is crucial to avoid major complications. Herein, we present an European individual living in the United States who underwent routine colon cancer screening in which the polyps that were biopsied revealed calcified Schistosoma eggs. Case Description/Methods: A 67-years-old male with past medical history of hypertension, goiter, and hyperlipidemia presented to the outpatient gastroenterology clinic for routine screening. Coloscopy done showed multiple colonic polyps, the largest being 1 cm in diameter. Pathology reported tubular adenomatous polyps with calcified Schistosoma eggs. Patient was asymptomatic and the physical exam was benign. On social and travel history, he pointed out that he lived in Angola from 1971-1973. Treatment with Praziquantel 600 mg three times daily was started, and the patient was asked to be followed up in 3 months. Negative serology was reported after treatment. Colonoscopy done 3 years later showed complete resolution of the polyps. Discussion: Schistosoma is a blood fluke causing Bilharziasis, an infection caused by freshwater parasitic worms. The parasite itself can be found living in certain freshwater snails. About 5 Schistosoma species have been identified to infect the human body with S. Mansoni and S. Japinicum being the main culprit for intestinal disease. Schistosomiasis is more prevalent in Sub-Saharan Africa with approximately 200 million cases reported worldwide. Infection occurs once the cercariae released by the snail penetrates the skin and begins its life cycle. Most individuals are asymptomatic. Migrating eggs cause bowel inflammation by triggering granulomatous reactions resulting in ulcerations, blood loss, and scaring. The same is true for Host immune response. The most common symptoms for intestinal Schistosomiasis are chronic intermittent abdominal pain, poor appetite, and diarrhea. Chronic ulcerations can be seen in severe cases with strictures as late complications. A combination of Polypectomy plus Praziquantel is often use as treatment. Follow up Colonoscopy to assure resolution is recommended.Figure 1.: Endoscopic mucosal removal of a Cecal granular cell tumor.

Granular Cell Tumor of the Tongue: A Rare Case Presentation of a 14 Years Old Girl

Granular cell tumor or Abrikossoff ’s tumor is an infrequent tumor that can arise in most organs, and especially in the ENT area. It is a usually benign neoplasm, that can lead to a misdiagnose of malignancy. It affects both sex, between the fourth and the sixth decade. We present in this report a case of a 14 years old girl with a slowly growing lesion on the right lateral border of the mobile tongue. The biopsy showed a proliferation of large cells with a granular cytoplasm that expressed two immunohistochemistry markers: CD68 and S100 antibodies. Surgical resection was completed with a one centimeter margin.The rare issue about this case is the age of presentation: the age of the patient is 14, whereas this tumor usually affects adult patients.

Granular Cell Tumor of the Breast: Clinical Presentation, Pathological Diagnosis and Treatment

Introduction: Granular cell tumor is a rare neoplasm of soft tissue and only in 1% of cases, it can shows a malignant behaviour. It is presumed to be a tumor originating from perineural or putative Schwann cells of peripheral nerves. Materials and Methods: We reviewed five patients affected by Granular cell tumor of the breast treated between January 2011 and January 2021 at the Fondazione Policlinico Universitario Agostino Gemelli IRCCS of Rome, Italy. Results: All of the granular cell tumors presented as solitary, painless and firm lump, highly suggestive of malignancy. The radiological findings were heterogeneous and non-specific. All lesions presented as masses, more clearly evident on ultrasound as hypoechoic lesions, with irregular shape, blurred contours and borderline features. The tumors were composed of large polygonal cells with abundant eosinophilic granular cytoplasm and small, central nuclei, being immunohistochemically positive for S100, Vimentin (with variable staining), CD56; negative for HMB45, MelanA, AE1/AE3, EMA, and Desmin. Conclusion: Granular cell tumor is a rare, usually benign breast disease that can have very similar characteristics to breast cancer both clinically and radiologically. Treatment of choice consists in wide resection or lumpectomy with margin assessment (no ink on tumor).

Endobronchial granular cell tumor mimicking asthma

The article presents a 22 year old female being treated as a case of asthma without any benefit, whom was ultimately found to have an endobronchial growth which on biopsy revealed Granular Cell Tumor. Pulmonary Granular Cell Tumors are very rare benign tumors as less than 80 cases has been described since 1938, when it was first described.

Granular cell tumor of the cecum: Case report of mini invasive surgical resection and review of the literature.

Introduction and importanceGranular Cell Tumor (GCT) is a rare lesion with unclear histogenesis, predominantly described as a skin lesion. Visceral localization of GCT is even more rare with few cases reported in the literature. Nowadays GCT guidelines are not available.Case presentationA 45-year-old Caucasian woman was visited in our surgical department for significant weight loss (about 30 kg) during the previous 6 months. Colonoscopy showed a caecal polypoid lesion that was resected with a diatermic loop and classified as GCT. Microscopically, the neoplasm partially involved the mucosa and diffusely the submucosa, extending to the endoscopic resection margins. Because of the high risk of perforation during endoscopic radicalisation attempt, the patient underwent ileocecal resection. The postoperative course was uneventful.Clinical discussionGCT is a rare soft tissue neoplasm probably deriving from Schwann cells. The main treatment for GCT is an endoscopic mucosal/submucosal resection. Nevertheless, a radicalization of the lesion through a surgical attempt should be preferred when the endoscopic procedure is linked to a high risk of perforation.It is important to distinguish GCT from other polypoid lesions of the colon, due to its malignant potential (about 2%) and its relapsing capacity when margins are involved.ConclusionGTC is a rare neoplasm and as its diagnosis is made only histologically, it should be included in differential diagnosis of colonic polypoid lesions. Surgery can be considered the best choice when an endoscopic attempt of GCT lesions is linked to a high risk of colon perforation.

Malignant gastrointestinal neuroectodermal tumor: Cytologic, histologic, immunohistochemical, and molecular pitfalls

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare malignant primary gastrointestinal mesenchymal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology. In the context of FNA, the diagnosis requires a cell block and the use of significant resources including immunohistochemical stains and molecular testing. The differential diagnosis of GNET includes clear cell sarcoma (CCS), gastrointestinal stromal tumor (GIST), gastric schwannoma, metastatic melanoma, malignant perivascular epithelioid cell tumor (PEComa) and granular cell tumor, among others. Here we describe a case which was initially diagnosed as malignant granular cell tumor by FNA which was later revised to GNET following the finding of an EWSR1-ATF1 fusion gene rearrangement.

Granular cell tumor: An Italian case-report

We report a case of a 58-year-old woman with granular cell tumor (GCT) of the breast. The clinical and instrumental aspects were suggestive for breast cancer.The correct diagnosis was obtained with a paraffin histological examination of the lesion excised by the biopsy.The clinical peculiarities and the correlated therapeutic implications of this rare neoplasm are discussed in this manuscript.Although CGT is a rare condition, it has considerable importance among benign breast lesions that can be erroneously interpreted as carcinoma.

Multiple caecal granular cell tumours-a case report.

Granular cell tumours (GCTs) are generally benign neoplasms, which are believed to be of neural origin. They are uncommon in the gastrointestinal tract. They are rarely found in the colon and even more rarely found to be multiple. We present a case of a man who underwent a right hemicolectomy for a submucosal lesion and polyps and was found to have multiple nodules diagnosed as caecal GCTs with cellular atypia. While uncommon, this case shows it remains an important differential due to implications for patient management, given the often benign nature of disease.

Granular cell tumor presenting with perforation of fourth part of the duodenum: A case report.

IntroductionGranular cell tumors (GCT) are relatively rare neoplasms most commonly occurring in skin or soft tissues. GCT are thought to be of Schwann cell origin and strongly positive for s100 protein. GCT of the intestinal tract are usually asymptomatic and found incidentally in the esophagus on endoscopy.Case presentationHere, we present a case of GCT jejunum and the fourth part of the duodenum. The patient is a 41-year-old female who presented with abdominal pain and was subsequently found to have pneumoperitoneum with a perforation of the fourth part of the duodenum. Intraoperatively, there were multiple enlarged and hard mesenteric lymph nodes, which were found to be due to GCT involving the fourth duodenum and proximal jejunum.Clinical discussionThe occurrence of GCT in the gastrointestinal (GI) tract are even less common accounting for 5–9% of all GCT with very few cases reported in the duodenum. GCT of the GI tract are often asymptomatic, consequently leading to misdiagnosed delays in treatment.ConclusionIn the setting of GCT in the fourth part of the duodenum with evidence of locally advanced disease, local resection is the preferred treatment.

Granular cell tumour of cecum mimicking a neuroendocrine tumor

Granular cell tumor (GCT) is a benign soft tissue neoplasm generally believed to be of nerve sheath origin. It is most frequently seen in skin, subcutaneous tissue and oral cavity. GCTs are uncommon in gastrointestinal tract (GIT), in which the majority are located in the esophagus. In this article, we report a case of GCT involving cecum in a 22 years lady. She had a sessile polyp in the cecum which was thought to be NET. Typical histomorphology and expression of S-100 on immunohistochemistry confirmed the diagnosis.We have reviewed, the GCTs of cecum reported previously with emphasis on the differential diagnosis. To best of our knowledge, this is only the 3 case of GCT of cecum reported in the Indian literature. Colonic GCTs are extremely uncommon. This is just the third case of GCT of colon in Indian literature. GCTs pose a diagnostic challenge due to lack of symptoms or nonspecific symptoms. Awareness of this entity helps in preventing misdiagnosis as happened in this case and avoiding further unnecessary treatment.

Malignant granular cell tumor of the ulnar nerve: A case report of long-term follow-up and literature review

Background: The incidence of malignant granular cell tumor, an extremely rare Schwann cell-derived tumor with a poor prognosis, is reported to be approximately 0.2% of malignant soft tissue tumors. We report a case of a malignant granular cell tumor originating from the ulnar nerve.Case presentation: A 71-year-old woman presented with a mass in her right forearm. Magnetic resonance imaging showed a tumor with homogenous intensity of T1 and heterogeneous hyperintensity of T2, continuous with the ulnar nerve. Incisional biopsy revealed a malignant granular cell tumor, and marginal excision of the tumor was performed. Histologically, the tumor size was 9.2 cm and consisted of eosinophilic, granular polygonal to round and spindle-shaped cells, with vesicular and prominent nucleoli, and increased mitosis. Immunohistochemically, the tumor cells were positive for S-100 protein, CD68, H3K27me3, TFE3, and SOX10 and negative for smooth muscle alpha-actin, desmin, cytokeratin AE1/3, epithelial membrane antigen, and synaptophysin. The Ki-67 positivity rate was 12%. These findings were consistent with those of malignant granular cell tumors. In addition, no metastasis or recurrence was observed 15 years after the excision.Conclusion: Surgical resection is the standard treatment option. In our case, the diagnostic criteria for malignant granular cell tumors were histologically met. Patients with malignant granular cell tumors have a poor prognosis. However, no metastasis or recurrence was observed in this case 15 years after the surgery.

25912 Multifocal granular cell tumor affecting skin and scrotum in a child

Introduction: Granular cell tumors (GCTs) are soft tissue neoplasms of neural origin. Their most frequent location is in the dermis or subcutaneous tissue from head and neck, and the tongue. The most common presentation is as solitary painless nodules in adult patients. However, multifocal GCT has been described, most in children with genetic syndromes.

Intracranial meningioma in a pet rat: MRI findings

We herein report the magnetic resonance imaging (MRI) findings in a brain meningioma in a pet rat (Rattus norvegicus domestica). A 1.5-year-old pet rat was referred for depression, ataxia, tremors and bilateral nystagmus; a brain MRI was elected suspecting an intracranial neoplasia. The study was performed with a 0.25 T scanner. The MRI revealed a well-defined oval mass with a heterogeneous appearance, hyperintense in T1 and T2, and with extra-axial localisation and severe brain compression, the mass appeared strongly and diffusely contrast-enhancing. Euthanasia was elected, with the necropsy confirming the presence of a voluminous extra-axial mass. Histologically, a well-differentiated, benign meningotheliomatous meningioma was diagnosed, with the histochemical stains allowing one to exclude a granular cell tumour. To the best of our knowledge, this is the first report of MRI investigations on a pet rat intracranial meningioma.