Granular cell differentiation: A review of the published work

Expression of Melan-A in cutaneous granular cell tumours: a diagnostic pitfall

Morphological overlap exists between cutaneous granular cell tumours (GCT) and malignant melanoma, with the melanocyte-specific markers HMB45 and Melan-A commonly used to support the diagnosis of melanoma. We recently encountered several cases of GCT in our practice showing strong expression of Melan-A. The aim of this study was to establish the prevalence of positive immunohistochemical staining for Melan-A and HMB45 in a series of unequivocal GCTs. We also aimed to assess the prevalence of staining for PRAME (PReferentially expressed Antigen in MElanoma), a marker expressed in >80% of primary melanomas as well as many non-melanocytic tumours. A total of 20 cutaneous/subcutaneous GCTs were evaluated using Melan-A, HMB45 and PRAME immunohistochemistry. Staining for Melan-A and HMB45 was scored using a semiquantitative scale from 0 (absent) to 3+ (staining present in >50% of tumour cells). PRAME expression was recorded as either positive (>75% of cell nuclei staining) or negative. Melan-A expression was observed in four GCTs (20%), with strong and diffuse (3+) staining seen in two cases (10%), both from anogenital areas. Weak patchy nuclear PRAME expression was seen in every case, interpreted to be negative. HMB45 was also negative in all cases (100%). Our study demonstrates that Melan-A expression can be strong and diffuse in a subset of otherwise unequivocal cutaneous GCTs, which may cause diagnostic confusion with malignant melanoma. HMB45 and PRAME did not stain any of the GCTs in our series.

Granular cell tumor of the lung and tracheobronchial tree: Two case-presentation with a review of the literature

Pulmonary granular cells tumors (CGT) are rare tumors, that derive from Schwann cells. In the tracheobronchial and pulmonary tree, they remain a diagnostic challenge. There are no well-established criteria to differentiate between benign, atypical, and malignant GCT. Moreover, its real frequency in the respiratory tract is still unknown. Here, we represent 2 cases of bronchial and lung GCTs. We aim to highlight the frequency of all clinicopathological characteristics of this rare tumor in the tracheobronchial and pulmonary tree location based on our cases and the available literature in a large systematic review.

Granular variant of a histiocytic tumor on the toe of a cat: Case report and literature review

A 16-year-old female spayed domestic shorthaired cat was examined for lameness and a mass on the fourth digit of the right hindlimb. Cytologic examination of an aspirate of the mass revealed large discrete cells admixed with low numbers of well-granulated mast cells. The discrete cells contained single to many variably sized light pink to purple granules in their cytoplasm and had pleomorphic nuclei, with intranuclear cytoplasmic inclusions. Karyomegalic, binucleated and multinucleated cells were seen. Histologic examination of formalin-fixed sections of the excised mass showed a mildly infiltrative, unencapsulated, multinodular dermal mass that extended into the subcutis and consisted of similar discrete cells. On immunohistochemical staining, the tumor cells expressed ionized calcium-binding adapter molecule 1 (Iba1) and CD18. The tumor cells did not express CD3, CD20, CD117, pancytokeratin (AE1/AE3), melanoma antigen (Melan-A), multiple myeloma oncogene-1 (MUM1), melanoma-associated antigen (PNL-2), and S-100. Low numbers of tumor cells expressed CD204 and protein gene product 9.5 (PGP9.5). Granules were variably positive for Periodic-acid Schiff (PAS) and Alcian blue. On transmission electron microscopy, the cells contained filopodia, abundant endoplasmic reticulum, and moderate numbers of low-density membrane-bound granules. This case documents a previously undescribed granular variant of a histiocytic tumor in a cat.

Multimodal ultrasonography findings of extramammary granular cell tumors: Two case reports

Extramammary masses are infrequently encountered in breast examinations. They may occur in the chest wall and axilla as neighbors of the breast. It is important to determine the nature of the lesion. However, some benign tumors, such as granular cell tumors (GCTs), also show malignant characteristics, which leads to misdiagnosis. To the best of our knowledge, multimodal ultrasound features of GCT have not been elucidated. We report two cases of women with GCTs encountered upon breast cancer screening; the tumor was not located in breast tissue. The first patient was a 37-year-old woman who presented with a slow-growing mass in the right breast and the GCT was located in the pectoralis major muscle. The second patient was a 52-year-old woman who presented with a palpable left axillary mass and the GCT was located in the axilla. Mammography failed to detect the masses in the two patients upon breast cancer screening. However, two-dimensional ultrasonography revealed a solid heterogeneous hypoechoic mass. Shear wave elastography showed that the masses had an increased hardness compared with the surrounding tissue. Further contrast-enhanced ultrasonography showed that the contrast patterns of the two masses were different. In case one, contrast-enhanced ultrasonography showed an inhomogeneous annular high enhancement, and the dynamic curve showed rapid enhancement and regression. In case two, contrast enhanced ultrasound showed slight enhancement around the lesion but no enhancement inside. Postoperative pathology confirmed that the GCT was benign in both cases. The patients showed no signs of recurrence at the 2-year follow-up. Here, we report two cases and present the multimodal ultrasonography findings of this tumor for the first time. Radiologists and surgeons should be aware of these imaging manifestations and include them in their differential diagnoses.

Granular cell dermatofibroma: A potential diagnostic pitfall

Dermatofibroma, also known as “fibrous histiocytoma”, is one of the most common cutaneous soft-tissue tumours. Many variants of dermatofibromas have been described and knowledge of these variations is important to avoid a misdiagnosis of a possibly more aggressive tumour. Histological features of different variants can coexist in the same lesion, but typical common fibrous histiocytoma features are generally found, at least focally, in all cases. However, when cellular changes make up the majority of the lesion, the histopathological diagnosis can become more complex and requires immunohistochemical investigations for a correct nosographic classification. We report on the case of a cutaneous fibrous histiocytoma, “granular cell” variant, found on the left leg of a 74- year-old woman.

An Update on Cutaneous Granular Cell tumours for Dermatologists and Dermatopathologists

Granular cell tumours are rare soft tissue neoplasms which occur at a wide variety of sites and commonly involve the skin. Distinction between benign and malignant granular cell tumours is important because benign tumours are commonly cured by complete excision and malignant tumours commonly recur and cause fatal metastatic disease. Communication between the dermatologist and pathologist is also important, as the pathologist may provide false reassurance by evaluating a benign appearing part of a clinically malignant tumour. The following review summarises the current literature on the epidemiology, clinical presentation, pathology, radiology, treatment and prognosis of cutaneous granular cell tumours, with a focus on improving diagnosis and management for dermatologists and dermatopathologists.

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

Introduction

A 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 case

An 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.

Discussion

This 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.

Conclusion

This is a potentially safe and effective procedure for mediastinal granular cell tumors, with outstanding cosmetic advantages.

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Our case presented with a rare mediastinal dumbbell-shaped granular cell tumor.

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The tumor was resected using a combined posterior and uniportal VATS approach.

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This is a safe and effective procedure for mediastinal dumbbell-shaped tumors.

Granular Cell Dermatofibroma: When Morphology Still Matters

Dermatofibroma, also known as "fibrous histiocytoma", is one of the most common cutaneous soft-tissue tumors. Many variants of dermatofibromas have been described, and knowledge of these variations is important to avoid misdiagnosis of a possibly more aggressive tumor. Histological features of different variants can coexist in the same lesion, but typical common fibrous histiocytoma features are generally found, at least focally, in all cases. However, when cellular changes make up the majority of the lesion, the histopathological diagnosis can become more complex and requires immunohistochemical investigations for correct nosographic classification. We present the case of a cutaneous fibrous histiocytoma, "granular cell" variant, found on the left leg of a 74-year-old woman.

Granular Cell Tumor of the Hand: Unusual Malignancy of a Previous Benign Lesion: A Case Report

CASE

Malignant granular cell tumors are uncommon soft-tissue tumors. We describe a granular cell tumor that presented as a benign hand nodule diagnosed by biopsy and image. The patient refused local excision. After 15 years, the patient came back because of symptomatic growth, and a malignant granular cell tumor was diagnosed, with metastatic disease. Despite surgical disarticulation and adjuvant treatment, she died after 8 months. The pathological examination revealed the tumor had progressed to malignant behavior.

CONCLUSIONS

Our findings highlight the importance of a closer follow-up. Although unusual, we must be aware of the possibility of a change of behavior from benign to malignant granular cell tumor.

Three additional cases of non-neural granular cell tumor with novel immunohistochemical findings

BACKGROUND

Non-neural granular cell tumor (NNGCT) is an uncommon neoplasm of controversial histogenesis and its histopathologic differential diagnosis includes, in addition to conventional GCT, other dermal tumors that may exhibit granular cell change.

METHODS

Three patients with a diagnosis of NNGCT were identified in the authors' files. Hematoxylin and eosin-stained sections and immunohistochemical studies were performed.

RESULTS

Histopathological study of the three lesions showed dermal proliferation of granular cells arranged in thick fascicles between collagen bundles. The lesions showed positivity for Factor XIIIa, CD163, CD68, NKIC3, vimentin, ALK, fascin, and cyclin D1.

CONCLUSION

To our knowledge, positivity for cyclin D1 has not been reported to date in NNGCT. In borderline cases, where the diagnosis is unclear despite histopathologic and immunohistochemical findings, positivity for cyclin D1 may favor the diagnosis of NNGCT. Further investigations to assess the differentiation of this rare neoplasm are needed.

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.

Oral granular cell tumour: A multicentric study of 56 cases and a systematic review

OBJECTIVE

Granular cell tumour (GCT) is a benign neoplasm that originates from Schwann cells. Within the oral cavity, it usually appears as a lingual nodule and especially amongst female adults. Histologically, GCT shows a proliferation of polygonal cells with eosinophilic granular cytoplasm, which can be associated with a pseudoepitheliomatous hyperplasia (PEH). In this study, we analyse the main clinicopathological data of intraoral GCT and we compare our results with previous studies.

MATERIAL AND METHODS

We have studied a series of 56 cases of oral GCT in Spain and Brazil, and we have conducted a systematic review in PubMed, Web of Knowledge and Scopus databases, using the keywords: "granular cell tumour" and oral.

RESULTS

In our series, GCT appeared as an asymptomatic benign tumour that is more frequent in women and in the tongue. PEH was observed in 32% of the lesions. In the review, we collected 282 cases of oral GCT with a similar clinical profile; seven patients had multiple lesions, and 33% of the cases presented PEH. No cases of malignant oral GCT have been described to date. GCT is an uncommon oral benign neoplasm, mainly unique and asymptomatic, derived from Schwann cells.

CONCLUSIONS

Although the etiopathogenesis of this oral tumour is unknown, its characteristics suggest that it could have a reactive nature. Conducting a complete clinicopathological study in all intraoral GCT is fundamental in order to dismiss other entities, including oral carcinoma.

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.

Fibrous Papule: A Histopathologic Review

Fibrous papule (FP) is a common benign lesion located primarily in the nose. Although its histogenesis has been marred with controversies in the past, the dermal dendrocyte is now largely accepted to be the putative cell of origin. Histopathologic diagnosis of an FP is straightforward in most cases, which shows characteristics of an angiofibroma. Several histologic variants have been described, recognition of which is important to avoid a misdiagnosis and inappropriate treatment. This review presents a historical perspective into the histogenesis, discusses the histopathologic features and potential diagnostic pitfalls of classic FP, and lists the various histologic variants and their differential diagnoses.

Cutaneous epithelioid hemangiosarcoma with granular cell differentiation in a dog: a case report and review of the literature

We report a case of cutaneous epithelioid hemangiosarcoma in a dog in which the majority of the neoplastic cells displayed histologic and ultrastructural features similar to those seen in granular cell tumors (GCTs). This intersection of hemangiosarcoma and granular cell change adds to the argument that GCTs are heterogeneous in histologic origin and underlines the fact that pathologists should not consider all GCTs as a single entity. The combination of histology in typical areas of the tumor with ultrastructural changes and the correct immunohistochemical markers can facilitate the accurate diagnosis of tumors with granular cell differentiation. Besides characteristic intracytoplasmic PAS-positive granules and ultrastructural proteinaceous accumulation within single membrane vesicles (presumably lysosomes and phagolysosomes), we suggest the following combination of markers for the diagnosis of granular cell angiosarcoma and/or hemangiosarcoma: vimentin positive, NSE and/or S100 negative, CD31 positive. We propose that the histologic granular appearance represents a metabolic defect of the neoplastic cells, which supports variability in cell origin for granular cell differentiation.

Spinal Cord Compression in a Horse due to a Granular Cell Variant of Neurofibroma

A neurofibroma of granular cell subtype is described in a 7-year-old horse. The horse had a 3-month history of ataxia affecting the forelimbs and hindlimbs, suggesting a C1-C6 neuroanatomical localization. Post-mortem examination revealed an intradural mass arising from the right sixth cervical spinal nerve and compressing the spinal cord. Histologically, the mass was composed largely of wavy spindle cells (a mixture of Schwann cells, perineurial cells and fibroblasts) intimately associated with ropy collagen fibres. Approximately 25% of the spindle cells were swollen and contained densely-packed, eosinophilic and periodic acid-Schiff-positive cytoplasmic granules. Immunohistochemistry for S100 and glial fibrillary acidic protein antigens labelled a proportion of neoplastic cells, while the cytoplasmic granules were positive for S100 and neuron specific enolase. This is the first report of a neurofibroma with granular cell differentiation in an animal. Granular cell differentiation in other peripheral nerve sheath tumours of animals is briefly discussed.