Typical and Atypical Granular Cell Tumors of Soft Tissue: A Clinicopathologic Study of 50 Patients

Forearm Granular Cell Tumor: A Rare Entity

Granular cell tumors are uncommon benign masses. They occur rarely and are usually solitary, nontender lesions, with a tendency to occur in the head and neck region and a predilection for the tongue. A malignant variant is even less common. To date, its origin remains uncertain. We report the case of a 19-year-old Egyptian man who presented to the Kasr eini Plastic Surgery Clinic with a swelling on the posterior aspect of his right forearm. After surgical excision and histopathological examination, it was found to be a granular cell tumor. This finding was of interest because of the rarity of the neoplasm in general, but in particular because of the scarcity of its occurrence in this anatomic location and the patient's sex, and age group.

Antiangiogenics in Malignant Granular Cell Tumors: Review of the Literature

Granular cell tumors (GCT) represent 0.5% of all soft tissue sarcomas (STS), and when metastatic, they exhibit aggressive behavior and determine limited survival. Metastatic GCTs are relatively chemo-resistant; however, there is growing evidence of the benefit of using pazopanib and other targeted therapies in this histology. This is a review of the role of pazopanib and other targeted therapies in the treatment of GCTs, along with some insights on pathology and molecular biology described in GCTs. From 256 articles found in our search, 10 case-report articles met the inclusion criteria. Pazopanib was the most employed systemic therapy. The median reported time on therapy with pazopanib was seven months. Eight out of ten patients (80%) experienced disease control with pazopanib, while four out of ten (40%) patients achieved an objective RECIST response. Molecular studies suggested that antitumoral effects of pazopanib in GCT might be due to a loss-of-function of ATP6AP1/2 genes which consequently enhance signaling through several molecular pathways, such as SFKs, STAT5a/b, and PDGFR-β. Other reported targeted therapies for malignant GCTs included pazopanib in combination with crizotinib, which showed disease control for four months in one patient, and a PI3K inhibitor which achieved disease control for nine months in another patient. Dasatinib and megestrol were ineffective in two other different patients. Pazopanib has been demonstrated to be active in advanced GCTs and may be considered as a preferable treatment option.

Unraveling the Mysteries of Perineural Invasion in Benign and Malignant Conditions

Perineural invasion (PNI) is defined as the dissemination of neoplastic cells within the perineural space. PNI can be a strong indicator of malignancy and is linked to poor prognosis and adverse outcomes in various malignant neoplasms; nevertheless, it can also be seen in benign pathologic conditions. In this review article, we discuss various signaling pathways and neurotrophic factors implicated in the development and progression of PNI. We also describe the methodology, benefits, and limitations of different in vitro, ex vivo, and in vivo models of PNI. The spectrum of presentation for PNI can range from diffuse spread within large nerves ("named" nerves) all the way through localized spread into unnamed microscopic nerves. Therefore, the clinical significance of PNI is related to its extent rather than its mere presence or absence. In this article, we discuss the guidelines for the identification and quantification of PNI in different malignant neoplasms based on the College of American Pathologists (CAP) and World Health Organization (WHO) recommendations. We also describe benign pathologic conditions and neoplasms demonstrating PNI and potential mimics of PNI. Finally, we explore avenues for the future development of targeted therapy options via modulation of signaling pathways involved in PNI.

Case report: Giant atypical granular cell tumor of the median nerve

Granular cell tumors are extremely uncommon soft tissue neoplasms that mostly occur in the head and neck regions. Granular cell tumors are generally benign, asymptomatic, and rarely involve the median nerve. Due to the lack of awareness about granular cell tumors, they are easily misdiagnosed and mistreated in primary hospitals. Here, we report a giant atypical granular cell tumor located on the median nerve, approximately 12 cm in size, with unusual symptoms of median nerve damage. Magnetic resonance imaging revealed a fusiform mass that was hyperintense on T2-weighted images and iso-hypointense on T1-weighted images. The mass was subsequently biopsied and found to be a granular cell tumor. The tumor was resected, and a pathological examination was performed. Pathological examination revealed necrotic foci, abundant eosinophilic granules, pustular ovoid bodies, and multiple mitoses. Immunohistochemical staining revealed that the tumor cells were positive for S-100, CD68, SMA, SOX-10, Calretinin, and TFE3. The integrated diagnosis was an atypical granular cell tumor. To the best of our knowledge, this is the first report of an atypical granular cell tumor involving the median nerve. Furthermore, we comprehensively reviewed the existing literature to provide a concise summary of the diagnostic criteria, imaging findings, and pathological features of granular cell tumors. Given the high recurrence and metastasis rates of this disease, granular cell tumors of the median nerve should be considered when a patient presents with symptoms of median nerve impairment. The diagnosis of atypical granular cell tumors relies on pathological examination. In addition, extensive resection and long-term follow-up are necessary to improve prognosis.

Esophageal Granular Cell Tumor: An Uncommon Cause of Dysphagia

Granular cell tumors (GCTs) are rare, typically benign, solitary neoplasms that can arise throughout the body, with reports of cases in the tongue, esophagus, colon, skin, vulva, and skeletal muscle, among others. Although GCTs are usually asymptomatic, esophageal GCTs can grow large enough to cause dysphagia. When developing the differential diagnosis for dysphagia, a broad consideration includes routine etiologies such as esophageal strictures, eosinophilic esophagitis, carcinoma, webs and rings, achalasia, and motility disorders, but GCTs may not readily come to mind. Due to their scarcity, this case report is presented to raise awareness of esophageal GCTs and emphasize key goals for diagnosing and managing this uncommon yet treatable cause of dysphagia. This case report details the clinical course of a patient presenting with a chief complaint of difficulty swallowing that was found to be caused by a subepithelial esophageal tumor discovered with esophagogastroduodenoscopy (EGD) and endoscopic ultrasound (EUS). Histopathological studies paired with immunohistochemical investigations of a tissue biopsy confirmed the etiology of the offending esophageal mass to be a GCT. The patient's dysphagia resolved after endoscopic mucosal resection of the GCT, and follow-up evaluations have remained negative for recurrence. This case highlights the esophageal GCT as an uncommon source of dysphagia and the need for EGD and EUS evaluations of subepithelial esophageal lesions accompanied by histopathological analysis for a definitive diagnosis of GCT.

Mutations involving TGFB and MAPK may be associated with malignancy in granular cell tumors

Granular cell tumors (GrCTs) are mesenchymal neoplasms of presumed schwannian differentiation that may present as solitary or multifocal lesions with excision usually being curative. A minority of cases, however, show histological features associated with an increased risk for metastasis and are highly aggressive leading to death in about a third of cases. While benign and malignant cases have been shown to harbor mutations in the H + ATPase genes, there is only limited data examining molecular aberrations associated with malignancy. The departmental archives were searched for cases of atypical/malignant GrCTs. Clinical and histopathological features were noted. Whole-exome sequencing was performed. Three cases of malignant GrCTs and one case of atypical GrCTs were included. All three malignant tumors metastasized to distant sites with a median disease-free survival of 16 months and an overall follow-up time of 35 months. Whole-exome sequencing showed mutations involving TGFβ and MAPK pathways in all four tumors. Although the cohort size is small, our preliminary findings suggest that mutations involving the TGFβ and MAPK pathways may be associated with tumor progression or malignant transformation in GrCT pathogenesis.

Malignant Granular Cell Tumor of the Lower Extremity in an Adolescent Male

Granular cell tumors (GCTs) are extremely rare soft tissue tumors, with only 2% of tumors being malignant. Malignant GCTs are more often seen in women between the ages 40 and 60. There has been no case reported of a malignant GCT in a pediatric patient. We present a case of a 14-year-old male who presented with a large mass in his left lower extremity. After being biopsied, the mass was diagnosed as a malignant GCT. The tumor was completely excised with wide margins and close follow-up with the patient continued.

Atypical cytological presentation of granular cell tumour: Tumour-associated fibrosis may affect fine-needle aspiration cytology accuracy

The cytological features of granular cell tumour (GCT) are generally quite typical but, in some cases, the fine needle aspiration cytology (FNAC) diagnosis of GCT may be difficult or impossible because of unusual sites of onset or equivocal cytological features. In this report, two GCTs with atypical FNAC features are described in order to investigate the causes and provide possible diagnostic tips. From a series of nine histologically proven GCTs, two inconclusive FNAC cases were retrieved. Smears were poorly cellular showing isolated naked nuclei, anisonucleosis, granular chromatin and occasional small nucleoli. The background was finely granular in one case. Histological controls of these cases revealed marked fibrosis. Tumour-associated fibrosis in GCT is variable and does not seem to influence clinical behaviour but it influences the harvest and the integrity of granular cells collected by FNAC. When GCT smears are poorly cellular, attention should be paid to the granular background and to the few granular cells, if any, as they might be the only features to suggest a GCT.

Epithelioid Cutaneous Mesenchymal Neoplasms: A Practical Diagnostic Approach

Epithelioid cells are rounded or polygonal cells with abundant eosinophilic or clear cytoplasm and ovoid to round nuclei, superficially resembling epithelial cells. Cutaneous mesenchymal neoplasms composed predominantly or exclusively of epithelioid cells are relatively uncommon and can cause considerable diagnostic difficulties due to overlapping histologic features among heterogeneous groups of tumors. Familiarity with practical diagnostic approaches and recognition of key histopathologic features are important for correct diagnosis and management. This review summarizes the histologic features of epithelioid cutaneous mesenchymal neoplasms and discusses their differential diagnoses from malignant melanomas and carcinomas.

Granular cell tumor a study of 42 cases and systemic review of the literature

BACKGROUND

Granular cell tumor (GCT) remains a diagnostic clinicopathologic problem because the exact frequency of its detailed morphological and clinical characteristics is unknown as most observations are collected from small series or isolated cases. Herein, our aim is to highlight the frequency of all clinicopathological characteristics of this rare tumor based in our series and the available medical (PubMed) literature.

MATERIAL AND METHODS

42 cases were evaluated for: tissue layers involved by the tumor (in skin and mucosae), growth pattern, nuclear pleomorphism, mitotic index, necrosis, spindling, calcification, hyalinization, and pustule-ovoid bodies of Milian, as well as perineural and vascular invasion, and the presence of adjacent epithelium changes, and lymphocytes and eosinophils infiltration., Follow-up was analyzed. The tumors were subclassified into benign, atypical and malignant according to Fanburg-Smith criteria and into benign or GCT of uncertain malignant potential according to Nasser criteria. The same characteristics were analyzed for 1499 cases reviewed according to PRISMA guidelines.

RESULTS

In the current series, the mean age at diagnosis was 45.8 years (range 6-69 years). Most patients were females (60 %) and the involved organs were by descending frequency: skin and subcutaneous tissue, bronchus, esophagus, breast, tongue, larynx, pharynx, gingiva, trachea, right colon, vulva, and hypopharynx. No recurrence or progression was seen, despite 32 cases were incompletely excised, with the exception of one malignant tumor. The growth pattern was either infiltrative (85.71 %) or well limited (7.14 %). Sixteen tumors had vesicular nuclei. Mitotic activity was found in two tumors. Lymphocytic infiltration was found in 14 tumors. Eosinophils were present in 6 cases. One GCT of the right colon showed extensive calcification and hyalinization. Perineural invasion was noted in 6 lesions. No vascular invasion was found. One tumor was clinically malignant and the patient died 2 years after diagnosis. Medical literature review showed similar results in terms of frequency of the reported clinical and morphological features. Among cases with available follow up, almost 20 % showed positive margins and of those 20 % developed local recurrence. According to the Fanburg-Smith criteria, 72 % would be benign, 17 % atypical and 11 % malignant tumors, while according to those of Nasser, 93 % would be benign and 7% of uncertain malignant potential. However, true malignancy, as affirmed by metastasis of GCT is found in almost 2.5 % of the cases.

CONCLUSION

GCT is a usually benign tumor, affecting any anatomic location. Necrosis and mitotic activity seem to be the most effective histologic criteria for detecting aggressive tumors, but the presence of metastasis (2.5 % of the cases) remains the most accepted definitive criterion for diagnosis of malignant GCT.

Desmoplastic stromal changes in cutaneous neural granular cell tumors: An under-recognized histopathologic feature of diagnostic and prognostic importance

BACKGROUND

Granular cell tumors (GCTs) are uncommon mucocutaneous and soft tissue neoplasms with distinctive histopathologic appearance but controversial histogenesis. Herein, we report a variant of cutaneous GCT featuring extensive desmoplastic stroma which may result in diagnostic difficulties with mesenchymal proliferations, particularly a dermatofibroma.

METHODS

Following a recent case of GCT with prominent stromal desmoplasia, we reviewed all cases diagnosed as GCT during the past 10 years accessioned at the dermatopathology unit in a tertiary university hospital.

RESULTS

Three additional cases with a similar excessive connective tissue were identified out of a total of 49 GCTs. Cytoplasmic granularity was often subtle and focal, S100 expression was weak, and nuclei had a tendency to show spindling in tumor cells entrapped within the desmoplastic areas. Of note, nuclear spindling is one of the criteria used to diagnose an atypical/malignant GCT.

CONCLUSION

We propose the term "desmoplastic GCT" for these tumors, which not only appropriately addresses the stromal changes but also raises an awareness of GCT being one of the cutaneous tumors which may show stromal desmoplasia. Differential diagnostic difficulties apart, awareness of this phenomenon is important so that desmoplasia and resultant spindling are not linked with potential aggressive behavior.

Smooth Auricular Cutaneous Granular Cell Tumor Mimics Epidermoid Cyst

Granular cell tumor (GCT) is a rare, benign neoplasm of Schwann cell origin. GCT is composed of cells with eosinophilic granular cytoplasm. GCT presents as a solitary painless nodule. Because of their subtle clinical presentation, GCTs are often misdiagnosed. This report of a 47-year-old woman with an auricular GCT serves to highlight that complete excision and histopathological evaluation should be attempted even in apparently benign cases, to ensure complete cure.

Metastasizing Malignant Granular Cell Tumor (Abrikossoff Tumor) of the Anterior Abdominal Wall, with Prolonged Survival

Malignant granular cell tumor (MGCT) is a rare high-grade mesenchymal tumor of Schwann cell origin. MGCTs commonly affect thigh, extremity, and trunk; however, involvement of the abdominal wall is quite rare. It has poor prognosis with 39% mortality rate in 3-year interval. We report a 50-year-old female who had MGCT arising in the anterior abdominal wall and developed massive metastatic deposits in both lungs and in the right inguinal lymph nodes, with prolonged survival for 11 years. A brief review of the literature is presented.