Granular cell angiosarcoma of the skin: histology, electron microscopy and immunohistochemistry of a newly recognized tumor

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.

Granular Cell Basal Cell Carcinoma of the Skin. Report of a Case with Immunocytochemical Positivity for Lysozyme

Granular cell tumors have been described in many sites throughout the body. To our knowledge, few cases have been described in the literature. We report here the sixth case, in which positivity for lysozyme was also observed for the first time. The problems of the histogenesis and differential diagnosis of this rare variant of basal cell carcinoma are also discussed.

Bilateral multifocal upper extremity atypical granular cell tumors presenting as long-standing right wrist and left hand masses in a 15-year-old African-American female

Granular cell tumor (GrCT) is a benign nerve sheath tumor. Atypical and malignant variants of GrCT are rare but have been well described. We report a case of multifocal symmetric atypical GrCT in the bilateral hand/wrists of a 15-year-old African-American female. The initial clinical impression for both masses was favored to be ganglion cysts. Ultrasound findings of both masses revealed hypoechoic soft tissue lesions with some internal echogenicity favoring complex cysts. On excision, both masses were histologically circumscribed, lobulated and attached to tendon. Large epithelioid cells with abundant granular eosinophilic cytoplasm arranged in syncytial cords and trabeculae percolated through collagen. Many cells had pleomorphism and/or prominent nucleoli. Mitotic figures, spindling, high nuclear-to-cytoplasmic ratio and necrosis were absent. Both masses showed diffuse S100 protein but negative desmin and pancytokeratin expression. Ki-67 index was 1% to 2%. p53 was positive in 5% to 10% of nuclei. Both masses met criteria for atypical (but not malignant) GrCT. Our case shows that atypical GrCT may be not only multifocal but also symmetric. We speculate that migration of defective neural crest stem cells along both upper limb buds during embryogenesis may have allowed these essentially identical tumors to arise in similar locations bilaterally simultaneously.

Gastric Epithelioid Stromal Tumor (Leiomyoma) With Granular Changes

A unique case of gastric epithelioid stromal tumor (leiomyoma) demonstrating granular changes is reported. Microscopically, the tumor was composed of polygonal or fusiform cells with a coarse, granular eosinophilic cytoplasm, focally admixed with fascicles of spindle-shaped cells. A marked lymphoid infiltrate forming follicles was also a characteristic finding. Immunohistochemically, these cells were positive for alpha-smooth-muscle actin, HHF-35 (muscle-specific actin), and NKI/C3 but negative for desmin, S100 protein, vimentin, lysozyme, and Mac-387. This case demonstrates that granular cell changes and prominent lymphoid aggregates are not limited to gastric stromal tumors with neural differentiation.

A collision tumor consisting of granular cell tumor and adenocarcinoma in the uterus of an aged djungarian hamster

A neoplastic nodular lesion consisting of an admixture of granular cell tumor and adenocarcinoma was found in the uterus of a 26-month-old Djungarian hamster. Neoplastic cells of the uterine adenocarcinoma showed an epithelial nature in their growth patterns and by cytokeratin-immunopositive reaction, exhibiting nuclear pleomorphism. The granular cells had an abundant amount of fine granular eosinophilic cytoplasm and eccentric or central nuclei with no nuclear atypia; the granular structures were positive for periodic acid-Schiff with diastase resistance and were confirmed as lysosomes/autophagosomes by electron microscopy; immunohistochemically, the cells reacted to desmin, vimentin and α-smooth muscle actin and negatively for neurogenic, histiocyte/macrophage or epithelial markers, indicating smooth muscle origin. Because these tumors were generated from different cell origins, a diagnosis of collision tumor was made.

Granular cell atypical fibroxanthoma: case report and review of the literature

We present a case of granular cell atypical fibroxanthoma of the scalp. The neoplasm occurred as a tender nodule on the frontal scalp of an 82-year-old Caucasian man. Histology demonstrated a diffuse proliferation of atypical epithelioid cells with abundant granular cytoplasm. Many of the cells had large irregular nuclei and atypical mitotic figures were present. Immunohistochemical stains were positive for CD68 and procollagen 1 and negative for cytokeratin, HMB-45 and S-100 protein. The granular cell phenotype has been observed in other cutaneous neoplasms including granular cell tumors, dermatofibromas, dermatofibrosarcoma protuberans, fibrous papules, basal cell carcinomas, leiomyosarcomas, angiosarcomas and primitive polypoid granular cell tumors. We discuss the differential diagnosis and review the previously reported cases of this rare variant of atypical fibroxanthoma.

Fibrous papule of the face with granular cells

Fibrous papule of the face is a common benign lesion located most often on the nose. It presents usually as a single small, firm, skin-coloured papule and is often misdiagnosed as melanocytic naevus, wart or small nodular basal cell carcinoma. Histopathologically, the lesions are characterized by involvement of the upper dermis by a fibrovascular proliferation and scattered triangular or stellate, often multinucleated cells. Uncommon histopathologic variants of fibrous papule of the face include hypercellular, clear-cell, pleomorphic, pigmented, inflammatory and granular-cell types. We present here a patient with the syndrome of familial cancer and fibrous papule of the face with granular cells. The granules stained strongly with PAS stain, as well as with CD68 and NKI/C3 immunostains, whereas S-100 protein resulted negative. In our patient the mutations in the 2 most often affected DNA mismatch repair genes of Muir-Torre syndrome were not found, therefore the origin of the familial cancer syndrome remains unknown. Probably the occurrence of the granular-cell fibrous papule of the face was coincidental.

Malignant granular cell tumor with unusual histological features

Malignant granular cell tumor, although uncommon, should be differentiated from a number of granular cell-containing tumors. Reported herein is a distinctive variant of malignant granular cell tumor, clinically presenting as a rapidly enlarging scrotal mass, in which some areas morphologically displayed features indistinguishable from Kaposi sarcoma. Cells in areas simulating Kaposi sarcoma were immunohistochemically the same as typical granular cells in other portions of the tumor. The recognition of this pattern is important because it may predominate and overshadow the original nature of tumor.

HMB-45 and Melan-A are Useful in the Differential Diagnosis Between Granular Cell Tumor and Malignant Melanoma

Granular cell tumors (GCTs), especially if atypical or malignant, may share cytomorphologic and architectural features with malignant melanoma, when the latter shows granular cell change. In many cases, these neoplasms can be differentiated from each other on histologic grounds, but distinction may sometimes be challenging. By immunohistochemistry, both tumors are strongly positive for S-100 protein and frequently express other nonspecific markers such as CD68, NSE, and NKIC3. In the current study, we reviewed 60 cases of conventional cutaneous, mucosal, and visceral GCT and studied the use of immunoperoxidase staining for the differential diagnosis between malignant melanoma and GCT. Immunohistochemical stains for S-100 protein, A, HMB-45, and microphthalmia transcription factor (MITF) were performed in all cases. All of the tumors were positive for S-100 protein. MITF immunostaining was diffusely positive in 53 (88%) cases, focally positive in three (5%) cases, and negative in four (7%). Fifty-seven (95%) tumors were negative for Melan-A, one case was focally positive, and two cases showed rare positive tumor cells. None of the tumors expressed HMB-45. In conclusion, GCT and malignant melanoma can be reliably differentiated on the basis of immunohistochemical stains in the majority of cases. Although not always positive in malignant melanoma, in this context, HMB-45 expression seems to be 100% specific for the diagnosis of melanoma. Melan-A is slightly less specific, with rare cases of GCT showing focal positivity. MITF is not useful in this differential-93% of the GCTs in our series showed nuclear reactivity for this marker. The latter finding highlights the limited specificity of this antibody in the diagnosis of melanocytic tumors.

Dermal non-neural granular cell tumour (so-called primitive polypoid granular cell tumour): a distinctive entity further delineated in a clinicopathological study of 11 cases

AIMS

Cutaneous and soft tissue granular cell tumour is a well-characterized benign neoplasm of neural origin. However, there remains a subcategory of granular cell tumour, first described by Le Boit as 'primitive polypoid granular cell tumour', that shows no obvious line of differentiation. The aim of this study is to further the characterization of this lesion by undertaking a clinicopathological review.

METHODS AND RESULTS

Eleven cases of dermal non-neural granular cell tumour were retrieved from one of the authors referral archives (E.C.) and both the histology and immunohistochemistry reviewed. Clinical data with follow-up were obtained from the referring pathologists. The lesions most commonly occurred in young to middle-aged adults (nine cases, median = 33 years, age range 6-56 years), with a slight female predominance. They presented as painless nodules, mainly on the extremities or face. Local excision was the treatment of choice and up to date follow-up reveals no sign of recurrence. Histologically, eight cases were polypoid, while three cases were endophytic. The tumours were composed of elongated spindle-shaped to polygonal or round cells with prominent granular cell change, and tumour nuclei showing mild focal atypia to rare moderate atypia. Mitotic activity ranged from one to nine mitoses per 10 high-power fields (median = 2, mean = 3.8). Immunohistochemical labelling of the tumour cells demonstrated expression for NKI-C3 (n = 11), focal, weak positivity for CD68 (n = 10) and FXIIIa (n = 2). There was negative staining for S100 protein, smooth muscle actin, Melan-A, CD34, desmin and cytokeratin.

CONCLUSIONS

This analysis of 11 cases contributes to the characterization of this recently described entity, which despite some atypical histological features and no obvious line of differentiation, behaves in a completely indolent fashion.

Primitive Nonneural Granular Cell Tumors of Skin

A rare subset of distinctive cutaneous nonneural granular cell tumors was described by LeBoit et al in 1991 and termed "primitive polypoid granular-cell tumor." Herein, we report our experience with 13 similar, distinctive nonneural granular cell tumors. Affected patients included 7 males and 6 females ranging in age from 5 to 83 years (mean, 25 years; median, 16 years). These cutaneous lesions involved the back (5 cases), neck, shoulder, thigh (2 cases each), chin, and elbow (1 case each). Clinically described as smooth, nontender cutaneous nodules, the tumors ranged in size from 0.2 to 2.8 cm (median, 0.8 cm) and were present from months to years before excision. Mitoses numbered from 1 to 6 per mm (median, 2). Eight of the lesions were polypoid, based in the papillary dermis with extension to the superficial dermis and associated with an epithelial collarette. Five of the lesions were situated deeper in the reticular dermis with limited extension into the subcutis but clinically were also nodular. All the tumors were well circumscribed and composed of spindled to ovoid cells with abundant granular, eosinophilic cytoplasm and vesicular nuclei with small prominent nucleoli. Immunohistochemistry revealed reactivity only for NKI-C3 (11 of 12 cases), CD68 (7 of 11 cases), and NSE (5 of 10 cases); S-100 protein as well as other melanocytic, epithelial, and myoid markers were uniformly negative. All 13 of the lesions were locally excised and in the 8 cases with adequate follow-up ranging from 13 to 126 months (mean, 68 months; median, 41 months), none has recurred locally. However, one tumor (case no. 11) gave rise to a local lymph node metastasis 25 months after presentation, but the patient is currently disease-free 70 months after lymphadenectomy. These cutaneous granular tumors do not appear to be neural or Schwannian in nature, but their precise line of differentiation is unknown.

Granular cell atypical fibroxanthoma

We report on two patients with granular cell atypical fibroxanthoma. Both neoplasms were solitary, light-tan, dome-shaped papules on sun-exposed areas of the head in two elderly white men. Microscopically, these neoplasms showed a dermal proliferation of pleomorphic granular cells with irregular hyperchromatic nuclei, multinucleated cells, and scattered mitoses. Immunohistochemical stains were positive for CD68 and vimentin and negative for Melan-A or human melanoma black (HMB)-45, S-100 protein, pancytokeratin, and actin, consistent with atypical fibroxanthoma. The differential diagnosis of granular cells in neoplasms containing cytological pleomorphism is challenging in view of the many different neoplasms that may present with granular cytoplasm. These include the conventional granular cell tumor and its malignant form, leiomyoma, leiomyosarcoma, dermatofibroma, dermatofibrosarcoma protuberans, and angiosarcoma.

Vascular tumors of the skin: A selective review

Cutaneous vascular proliferations are a vast and complex spectrum. Many appear as hamartomas in infancy; others are acquired neoplasms. Some vascular proliferations are hyperplastic in nature, although they mimic hemangiomas, i.e., neoplasms. The vast majority of the vascular lesions are hemangiomas. Between the hemangiomas and frankly angiosarcomas, there is a group of neoplasms that are angiosarcomas, albeit ones of low grade histologically and, probably, biologically. The term "hemangioendothelioma" has been created to encompass these neoplasms. Vascular proliferations are, fundamentally, composed of endothelial cells. Some hemangiomas, however, contain also abundant pericytic, smooth muscle, or interstitial components, or a combination of them. These heterogeneous cellular components are present usually in hemangiomas. Some of the newly described vascular proliferations, however, are difficult to differentiate from some of the angiosarcomas. Others are markers, occasionally, of serious conditions such as Fabry's Disease (angiokeratoma) and POEM's syndrome (glomeruloid hemangioma). Kaposi's sarcoma continues to be an enigma. The demonstration of Herpes virus 8 in this condition raises doubt about its neoplastic nature. The demonstration of endothelial differentiation of its nodular lesions is tenuous and its true nature remains unresolved. While physicians have known about post-mastectomy angiosarcomas from the origin of the radical mastectomy, a new group of unusual vascular proliferations of the mammary skin are being defined. These lesions arise in the setting of breast-conserving surgical treatment with adjuvant radiation therapy. The incubation period is usually 3 to 5 years, in contrast with the 10, or more, in classical cases of post-mastectomy angiosarcoma. These lesions usually are subtle, both clinically and histologically, in contrast with the "classical," dramatic presentation of mammary angiosarcoma. The spectrum of findings ranges from "simple" lymphangiectasia-like vascular proliferations to unequivocal angiosarcomas. The pathogenesis of these lesions remains a mystery. There are very few clues that allow one to separate hemangiomas from angiosarcomas. The presence of heterologous cellular elements and, particularly, well-developed smooth muscle components tends to favor a hemangioma. Similarly, the presence of thrombosis usually supports hemangioma. Nevertheless, there are no unequivocal or reliable individual diagnostic criteria. A thorough knowledge of the different conditions and their differential diagnoses eventually leads to the proper diagnosis in most cases.

Oncocytic metaplasia occurring in melanoma

BACKGROUND

Oncocytosis is a cellular feature characterized by the presence of a finely granular eosinophilic cytoplasm due to the accumulation of mitochondria. While this histologic trait can be found in normal tissues, it is also seen pathologically as a degenerative phenomenon. We recently reviewed a spectrum of oncocytic melanocytic nevi that did not have clinical significance. We now describe similar changes in melanoma.

METHODS

We retrospectively reviewed 12 melanomas noted to have prominent granular eosinophilic cytoplasm and completed ultrastructural studies. We obtained patient histories and clinical follow-up information from the patients' physicians.

RESULTS

All cases were primary melanomas and showed prominent oncocytosis in the majority of the lesional melanoma cells. Oncocytosis was observed in both melanoma in situ and invasive melanoma with a wide range of Breslow thicknesses (range, 0.45-5.05 mm). It occurred in the presence and absence of ulceration, regression, vascular invasion, and brisk tumor infiltrating lymphocytes. Ultrastructural studies revealed melanocytes with numerous distorted mitochondria.

CONCLUSION

Melanoma is capable of presenting in a variety of histologic guises, including oncocytic change. While our observations are preliminary, this pathologic curiosity likely represents a degenerative phenomenon of little prognostic importance.

Oncocytic metaplasia occurring in a spectrum of melanocytic nevi

Oncocytosis is defined as a metaplastic change characterized by the presence of cells with finely granular eosinophilic cytoplasm caused by the accumulation of mitochondria. Although this histologic feature can be found in normal tissues, it can also be seen pathologically as a degenerative phenomenon, where an accumulation of mitochondria is thought to compensate for an uncoupling of oxidative metabolism secondary to cellular aging. Oncocytic metaplasia can be observed in a variety of cutaneous lesions but, to our knowledge, has not been described in melanocytic nevi. We retrospectively reviewed 87 melanocytic nevi from 83 patients that showed significant oncocytic change. We obtained patient clinical history through surveys completed by the patients' physicians. Ultrastructural studies were performed on 4 representative nevi to confirm the presence of increased mitochondria. We prospectively reviewed 100 randomly selected nevi looking for oncocytic changes. We subsequently did not find any correlation with patient demographics or medical histories. Histologic evaluation showed granular eosinophilic cytoplasm in 75% or greater of lesional cells in two thirds of cases. This phenomenon occurred in all types of melanocytic nevi. Ultrastructural studies revealed melanocytes with numerous mitochondria in close apposition to melanosomes. Focal oncocytic change was identified prospectively in 38 of 100 randomly selected melanocytic nevi. We conclude that oncocytosis in melanocytic nevi is a relatively common and underrecognized phenomenon.

COL1A1-PDGFB gene fusion demonstrates a common histogenetic origin for dermatofibrosarcoma protuberans and its granular cell variant

Granular cell variant of dermatofibrosarcoma protuberans is very rare with only one report of two cases. We report a new case in which we demonstrated the presence of the dermatofibrosarcoma protuberans-specific COL1A1-PDGFB fusion from paraffin-embedded tissue. This case analysis demonstrated the utility of molecular genetics as a powerful tool for the diagnosis of atypical forms of dermatofibrosarcoma protuberans.

Granular Cell Variant of Atypical Fibroxanthoma

We report a case of atypical fibroxanthoma of the ear in which the dominant part of the tumor has granular cell appearance. Areas identical to conventional atypical fibroxanthoma were present only at the lateral infiltrating borders. Histologically the granular cells resembled those of the classical granular cell tumors but exhibited significant pleomorphism and a high mitotic rate. Immunostains for vimentin, CD68 and NK1/C3 were positive but for S-100, HMB-45, myogenic and epithelial markers were negative. The predominance of the granular cells in an atypical fibroxanthoma supports the concept that a small subset of tumors with granular cell phenotype are of nonneural origin.

Dermatofibroma-like granular cell tumor

BACKGROUND

There have been several reports in the literature of dermatofibromas with granular cells. Here we report a granular cell tumor with the architecture of a dermatofibroma. This is the first report of this histological variant of granular cell tumor. The lesion was a 2.5-cm oval, hyperpigmented plaque present for "years" on the back of a 60-year-old African-American woman.

METHODS

The specimen was processed using formalin fixation and paraffin embedding. Tissue sections were stained with hematoxylin and eosin. Immunohistochemical studies were performed with antibodies directed against S-100 protein, neuron-specific enolase, and factor XIIIa.

RESULTS

Histopathologic examination revealed granular cells, some of which were spindle shaped, distributed singly and in small groups between collagen bundles resembling a dermatofibroma. Immunohistochemical studies showed the tumor cells to be positive for S-100 and neuron-specific enolase and negative for factor XIIIa.

CONCLUSION

The immunohistochemical findings support the diagnosis of a granular cell tumor with a dermatofibroma-like pattern.

Abnormal pigmentation of schwannoma attributed to excess production of neuromelanin-like pigment

Five cases of non-melanotic pigmented schwannoma with excess accumulation of neuromelanin are presented. The tumors were composed basically of spindle or fusiform tumor cells, compatible with those of classical schwannoma, together with varying numbers of tumor cells containing various amounts of light brown or grayish pigment. Fontana-Masson stain demonstrated argentaffin granules in some tumor cells of each tumor and bleaching with potassium permanganate abolished argentaffin reaction. Ultrastructural examination demonstrated the granules contained fine particles with heterogeneous density, occasionally together with coarse granular materials or amorphous high-density areas, indicating lysosome or autophagosome. Neither typical melanosomes nor neurosecretory granules were detected. In immunohistochemistry, neurogenic markers as well as CD68 were expressed in most tumor cells in each case and various numbers of tumor cells were positive for Leu7 and CD34. Lysozyme was also frequently positive in tumor cells, especially in granular cells. HMB45 was not expressed in any of the cases. These findings indicate that these cases are schwannomas with abnormal accumulation of neuromelanin-like pigment.

Electron microscopy in tumour diagnosis: continuing to complement other diagnostic techniques

The histopathological diagnosis of tumours has been transformed by immunohistochemistry. Used with experience and judgement, a panel of antibodies or antisera, combined when necessary with antigen retrieval, will enable the accurate typing of most problematic tumours. This has led many histopathologists to question whether the electron microscope has any residual utility for tumour diagnosis; the machines are large, costly to purchase and maintain, and will accept only minute samples of tissue. The following articles by Mierau and by Eyden, both strong advocates, comment on the current and future role of electron microscopy in tumour diagnosis.

Combined clear and granular cell leiomyoma of soft tissue: evidence of transformation to a histiocytic phenotype

AIMS

We present an unusual case of leiomyoma with a clear and granular cell pattern in which there was immunohistochemical evidence of transformation to a histiocytic phenotype.

METHODS AND RESULTS

A 64-year-old man presented with mild scrotal swelling and pain. A local excision was performed after the clinical diagnosis of epidermal inclusion cyst. In the pathological specimen, another tumour nodule was identified which was composed predominantly of clear cells, with an occasional mixture of granular cells. Immunohistochemical analysis demonstrated positive staining for vimentin, lysozyme, CD68 and HAM56, but complete negativity for desmin, alpha-smooth muscle actin, HHF35, S100 protein, neurone-specific enolase and CD34. Ultrastructural study revealed dilated rough endoplasmic reticulum, glycogen granules, abundant vacuolar structures and also thin microfilaments with subplasmalemmal dense bodies.

CONCLUSIONS

Based on these findings, we have interpreted it to be a rare case of leiomyoma with extensive clear cell and granular cell degeneration (combined clear and granular cell leiomyoma). This complete transformation of the immunohistochemical profile into the histiocytic phenotype has not been previously described in the literature.

Congenital CD34-positive granular cell dendrocytosis

Granular cell tumors involving the skin are mostly acquired lesions. The Schwann cell origin of these lesions is supported by positive immunostaining for S-100 protein and myelin basic protein. S-100- granular cell lesions rarely have been described in association with fibrous papules or dermatofibromas. The congenital variety of S-100- granular cell tumors occurs almost exclusively in the gingiva. The cell origin of these lesions is not well delineated. We report a hitherto undescribed case of a congenital cutaneous lesion which is histologically characterized by diffuse dermal infiltrates of S-100- but CD34+ granular dermal dendrocytes. The granular appearance of these CD34+ dendrocytes is attributed to an abundance of phagolysosomes. The pathogenetic mechanism of this unusual lesion remains to be elucidated.

Malignant granular cell tumor of soft tissue: diagnostic criteria and clinicopathologic correlation

Seventy-three cases of malignant, atypical, and multicentric granular cell tumors of soft tissue were studied to clarify criteria for malignancy and prognostic factors. Six histologic criteria were assessed: necrosis, spindling, vesicular nuclei with large nucleoli, increased mitotic activity (> 2 mitoses/10 high-power fields at 200x magnification), high nuclear to cytoplasmic (N:C) ratio, and pleomorphism. Neoplasms that met three or more of these criteria were classified as histologically malignant; those that met one or two criteria were classified as atypical; and those that displayed only focal pleomorphism but fulfilled none of the other criteria were classified as benign. Hence, 46 cases were classified as histologically malignant, 21 as atypical (3 were multicentric), and 6 as benign (all were multicentric). The patients with benign multicentric and atypical granular cell tumors had no metastases and there were no tumor deaths. In contrast, 11 of 28 patients (39%) with malignant granular cell tumor with follow-up information died of disease at a median interval of 3 years; 8 of 28 (29%) were alive with disease, and 9/28 (32%) were disease free (median intervals, 2 and 7 years, respectively). There were local recurrences in 9 of 28 malignant cases (32%) and metastases in 14 of 28 (50%) (median intervals, each 2 years). Forty-eight cases were studied immunohistochemically; 100% expressed vimentin, 98% S-100 protein, 98% neuron-specific enolase, 69% CD57, and 65% CD68. Alpha-smooth muscle actin, desmin, epithelial membrane antigen (EMA), cytokeratins (with CAM 5.2 and KL-1), chromogranin, and HMB45 were not detected. The proliferative index with Ki67 (MIB 1) was 10-50% in 14 of 25 malignant tumors (56%), and immunostaining for p53 was detected in 50% or more of tumor cells in 17 of 25 (68%); both of these factors were statistically significant with regard to the histologic classification as benign, atypical, or malignant. Ultrastructural examination of 13 benign, atypical, and malignant granular cell tumors showed engorgement of the cytoplasm with complex granules and lysosomes, as well as Schwannian features. By flow cytometric DNA analysis, two of six malignant tumors were aneuploid, two were hyperdiploid, and two were diploid. One atypical tumor was aneuploid and all 11 benign tumors were either diploid (9 cases) or hyperdiploid (2 cases). Statistically significant adverse prognostic factors with regard to survival included local recurrence, metastasis, larger tumor size, older patient age, histologic classification as malignant, presence of necrosis, increased mitotic activity, spindling of tumor cells, vesicular nuclei with large nucleoli, and Ki67 values greater [corrected] than 10%. This study defines clinical and morphologic criteria for malignancy in granular cell tumors and shows that malignant granular cell tumor is a high-grade sarcoma with a high rate of metastases and a short survival.

Cutaneous vascular proliferations. Part III. Malignant neoplasms, other cutaneous neoplasms with significant vascular component, and disorders erroneously considered as vascular neoplasms

In this third and last part of our review of cutaneous vascular proliferations we include malignant vascular neoplasms and a group of heterogeneous cutaneous neoplasms characterized by a significant vascular component. We also review some disorders that, in our opinion, have been erroneously considered as vascular neoplasms. We review the epidemiologic, histogenetic, clinical, and histopathologic aspects of Kaposi's sarcoma in its four distinctive variants (classic, African-endemic, immunosuppressive drug-associated, and AIDS-associated Kaposi's sarcoma). There is still controversy about whether Kaposi's sarcoma represents a reactive vascular proliferation or a true neoplastic proliferation. In any event, most authors believe that Kaposi's sarcoma does not produce metastatic disease, but rather develops in multifocal fashion. However, Kaposi's sarcoma may cause death, especially in immunosuppressed patients. Epithelioid hemangioendothelioma, Dabska's tumor, and retiform hemangioendothelioma are examples of low-grade angiosarcoma. In contrast, cutaneous angiosarcomas, including the clinical variants of angiosarcoma of face and scalp in elderly patients, angiosarcoma associated with lymphedema, and radiation-induced angiosarcoma are highly aggressive neoplasms with poor prognosis and most patients die within a short period after presentation. A group of benign and relatively frequent cutaneous neoplasms, including multinucleate cell angiohistiocytoma, angiofibroma, angioleiomyoma, angiolipoma, cutaneous angiolipoleiomyoma, and cutaneous angiomyxoma are here covered because of their significant vascular component. Finally, we review briefly a series of cutaneous disorders that have been erroneously considered as vascular neoplasms. Kimura's disease is an inflammatory reactive condition of unknown origin, "benign" angioendotheliomatosis is a reactive intravascular proliferation of endothelial cells that occurs in the skin as a response to a variety of stimuli, "malignant" angioendotheliomatosis is an intravascular lymphoma, and acral pseudolymphomatous angiokeratoma of children (APACHE) is better interpreted as a pseudolymphoma.

Dermatofibroma with granular cells

A new histologic variant of dermatofibroma, only briefly alluded to in dermatological literature is reported. This tumor was located in the back of a 24-year-old man. It was present for about 2 years and had a history of trauma 2 months before excision. The lesion showed similar characteristics to those of conventional dermatofibroma as well as the presence of groups of granular cells identical to those seen in granular cell tumors. It is important to recognize dermatofibroma with granular cells because it may be confused with a variety of benign or malignant soft tissue tumors containing similar granular cells that entail different significance or prognosis. The immunohistochemical study supports a granular cell change in a dermatofibroma instead of a granular cell tumor that has been traumatized, with secondary formation of a dermatofibroma reaction.

Malignant granular cell tumor: a case report and review of the recent literature

We report a case of an extremely rare neoplasm, malignant granular cell tumor (MGCT). The tumor occurred in the infratemporal fossa of a 30-year-old man, extended to the left orbital base, into the foramen ovale, and invaded the mandible. A granular cell tumor (GCT) was diagnosed by fine-needle aspiration and core needle biopsy of the mass. The patient underwent a radical subtotal debulking procedure followed by radiotherapy. He is alive with recurrent disease 12 months after presentation. Cytologically, the aspirated material was abundantly cellular showing large polygonal cells with ample granular eosinophilic cytoplasm, eccentric nuclei, and often prominent nucleoli. Histologically, the tumor consisted of solid sheets of similar cells that stained strongly with S-100 protein, neuron-specific enolase (NSE), and vimentin. There was moderate nuclear pleomorphism and broad zones of necrosis. Four mitotic figures per 100 high-power field (HPF) were counted. By electron microscopy, the cytoplasm of the tumor cells was filled with lysosomes. Although, some observers advocate that the diagnosis of a MGCT should be reserved for cases in which lymph node and/or distant organ metastasis is evident, we believe malignancy ought to be considered in any GCT with aggressive clinical course defined by persistent local recurrence and destruction of neighboring structures. Nuclear pleomorphism, necrosis, and presence of any mitotic activity should indicate malignancy.

Granular cell change in astrocytic tumors

Intracerebral granular cell neoplasms are uncommon. We report five hemispheric astrocytomas, all of which showed the distinctive features of granular cell change, being composed exclusively or predominantly of rounded cells with coarse granular eosinophilic cytoplasm and eccentrically placed nuclei. Four showed clear foci of transition from an anaplastic astrocytoma and contained lipidized as well as granular cells. In all tumors, the cytoplasmic granules were positive for periodic acid Schiff and resistant to diastase digestion, and there was focal glial fibrillary acidic protein expression. In addition, diffuse cytoplasmic positivity with epithelial membrane antigen antiserum was present, but in no case was there true membrane staining. Ultrastructural appearances were similar in four cases, showing the cytoplasm of tumor cells to be filled with membrane-bound autophagic vacuoles; bundles of intermediate filaments were also seen in some cells. Despite earlier controversy over the histogenesis of granular cell tumors, it is now clear that granular change is a degenerative phenomenon that, like lipidization, can occur in tumors of different cell types, including--rarely--astrocytic neoplasms. It is important that this histologic variant be recognized, as on a small biopsy sample diagnostic confusion with an infarct, demyelinating disease or a secondary carcinoma is a real possibility.

Cutaneous granular cell angiosarcoma

The majority of cutaneous angiosarcomas display typical architectural features of irregular anastomosing vascular channels in the dermis and subcutis. Nuclei are usually hyperchromatic and pleomorphic but the volume of cytoplasm of the neoplastic cells is often small. Diagnosis can be made readily on an adequate biopsy. We recently experienced difficulty diagnosing an angiosarcoma composed predominantly of cells with abundant granular cytoplasm. We were able to compare the present case with sections obtained from the only other reported example. The architectural expression of an anastomosing vascular pattern in areas of tumor, combined with the positive staining for Factor VIII-related antigen (FVIIIRAg) and Ulex europaeus agglutinin-1 (UEA1) enabled us to make a diagnosis of angiosarcoma. The tumor failed to stain for the other endothelial markers (CD31 and CD34) which were positive in the original case. A marker for lysosomes (CD68) stained the granules in both cases. The granular cell variant of cutaneous angiosarcoma is very rare. Diagnosis is possible by recognizing the typical anastomosing neoplastic vascular channels at the periphery of the lesion, and by use of a combination of lectin (UEA1) and immunohistochemical (FVIIIRAg, CD34 and CD31) endothelial markers.

Granular cell change in smooth muscle tumours of skin and soft tissue

Nine smooth muscle tumours, arising at a variety of sites and showing granular cell change of their cytoplasm, have been studied morphologically and immunohistochemically. The age of the patients ranged from 6 to 78 years (median 42 years); seven patients were female. Two tumours each arose in the dermis or subcutaneous tissue while the other five cases were situated in deeper soft tissue. Three of the lesions arose in the lower limbs, two in the pelvis and one each in the regions of the elbow, shoulder, breast and buttock. Follow-up in eight patients was available and revealed local recurrence in three and pulmonary metastases in two cases. All cases showed at least focally the light microscopic features of a smooth muscle tumour and demonstrated moderate to strong positivity for alpha-smooth muscle actin. Five were also HHF-35 positive and three were desmin positive. Noteworthy was strong positivity for the 'melanoma associated' antigen NKI/C3 in all cases. Six cases stained also weakly positive for NSE, but all were S-100 protein negative. The former is not specific but is the most reliable marker of lesions showing granular cell change. Granular cytoplasmic change represents simply a cytological phenotype, apparently representing a characteristic metabolic alteration, not exclusively associated with Schwann cell tumours. Tumours containing granular cells are best classified according to their line of specific cellular differentiation if possible.

Granular cell basal cell carcinoma. Light microscopy, immunohistochemical and ultrastructural study

Granular cell basal cell carcinoma (BCC) is a rare histological variant of BCC. In this, the fifth reported case, a 67-year-old male with BCC located on the nose, light microscopy examination showed a tumour with the classical configuration of nodular BCC, in which most cells had finely granular eosinophilic cytoplasm. Ultrastructural observation showed numerous lysosome-like granules filling the cytoplasm of tumour cells, along with numerous well-formed pentalaminate desmosomes. Immunohistochemical profile (including positivity for keratins C 5.2 and AE 1 and for Leu-M1), together with the presence of cytoplasmic tonofilament bundles and desmosomes, are consistent with the proposed epithelial origin of granular cells in this tumour.

Histologic and immunohistochemical studies of granular cell tumors in seven dogs, three cats, one horse, and one bird

In a retrospective study, granular cell tumors in six dogs (Nos. 1-6), three cats (Nos. 1-3), one horse (No. 1), and one cockatiel (Nymphicus hollandicus) (No. 1) and a meningioma with a granular cell component in one dog (No. 7) were examined histologically and immunohistochemically. These tumors were identified by histologic examination of surgical biopsy specimens, except in the horse, in which the tumor was an incidental finding at necropsy. These diagnoses were initially made by more than one pathologist. Five of the six granular cell tumors in the dogs were in the oral cavity; one of these was in the maxillary gingiva of a 6-month-old puppy. The tumors in the cats were located in the tongue, vulva, and digit. The tumor in the horse was in the lung, and the tumor in the cockatiel was in the periocular tissue. Histologically, all granular cell tumors were characterized by oval to polygonal cells of various sizes. The cells had abundant, pale, eosinophilic cytoplasm with distinct intracytoplasmic granules, distinct cell margins, and mostly central nuclei. In the dogs, the gingival tumor had a large amount of collagen tissue, the tumor in the tongue had dilated blood vessels, and the maxillary tumor in the puppy was more cellular than the other tumors. The tumors in the cats were more anaplastic than the other tumors; one, located in the digit, was considered malignant. The granules in all of the tumors stained with periodic acid-Schiff and were diastase resistant. On staining with Luxol fast blue, the granules of all tumors stained different shades of pink, with the exception of the tumor in the tongue of a cat, which stained bluish green. Immunocytochemically, all tumors except the tumor in the cockatiel reacted against antibodies to vimentin. The granular cell tumor in the lung of the horse and the intracranial meningioma in a dog reacted to the antibody S-100 protein; the tumor in the horse reacted to neuron-specific enolase; tumors in two dogs (gingiva and skin) reacted to L-antitrypsin, and the maxillary tumor also reacted to lysozyme; the malignant tumor in the digit of a cat and the periocular tumor in the cockatiel reacted to muscle common actin and actin; the tumor in the cockatiel also reacted to desmin. Results of these immunocytochemical studies suggest that granular cell tumors, like tumors composed of rhabdoid cells, clear cells, and oncocytes, can have similar morphologic features but be of different cellular origins.

Fibrous papule of the nose with granular cells: two cases

Two cases of fibrous papule of the nose (FPN) with granular cell features are presented and discussed. Both lesions have classic architectural features of FPN; however, the main stromal cells show large cytoplasmic granules of the type seen in granular cells. We are uncertain of the significance of these findings. Our hypotheses include a perifollicular granular cell reaction and a granular degenerative change of local dermal dendrocytes.

Bone lining (endosteal) cells and hematopoiesis: a light microscopic study of normal and pathologic human bone marrow in plastic-embedded sections

Human trabecular bone that encloses the bone marrow (BM) is covered by a single layer of thin, sometimes inconspicuous, flat, elongated (spindle-shaped) endothelium-like cells with a round or oval nucleus. These "bone lining" cells, or endosteal cells (EC), form a continuous membrane (endosteum) over the trabecular bone surfaces. In most cases, the composition and thickness of these cells do not vary unless the cells are in intimate contact with hematopoietic tissue. In that instance, they are seen as a single layer adjacent to hematopoietic tissue or as a zone of tightly packed or loosely arranged mononuclear (hematopoietic) cells, some apparently originating from the endosteum. In a reparative process, such as following BM harvest, during which bony trabeculae (BT) are mechanically fractured, these cells are seen giving rise to osteoprogenitor (osteoblasts and osteoclasts) cells. Occasionally, the EC appear similar to BM stromal cells (morphologically and by their association with collagen/reticulin fibers) and are best seen at or near the BT that are cut tangentially. Short processes extending from the EC towards the underlying osteocytes have also been observed, suggesting that a channel of communication exists between them and osteocytes. Our observations, coupled with the experimental findings of others (i.e., that hematopoietic stem cells are concentrated near the endosteum, that cells responsible for BM and stroma regeneration are derived from the endosteal layer, and that high concentrations of hematopoietic colony-stimulating factors are produced there), indicate that, in addition to functioning as a simple membranous covering layer for BT, the endosteum helps to support osteocytes and maintains mineral homeostasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrathoracic granular cell tumour in a dog

Multiple granular cell tumours occurred diffusely throughout the pleura of an adult German Shepherd Dog. The growths were scattered over the surface of the lungs, mediastinum and diaphragm. Histologically, the masses consisted of plump cords of cells with eosinophilic, weakly PAS-positive cytoplasmic granules. Electron microscopically, the granules consisted of a pleomorphic population of electron-dense granules. The predilection site in the dog is the tongue and this is the first report of an intrathoracic, pleural site of granular cell tumours in the dog.

Granular cell tumours revisited. An immunohistological and ultrastructural study

Twenty-five granular cell tumours were stained with a panel of antibodies to histiocytic, muscle, neural, neural crest, epithelial and endothelial markers. Electron microscopy was also performed in six cases. Twenty-four of the cases were similar morphologically and immunocytochemically. One case with features of an endothelial origin is described. The present study strongly supports the viewpoint that granular cell tumours are a distinct entity rather than being the common appearance of a group of lesions of differing histogenesis. Origin from a neural crest-derived peripheral nerve-related cell is favoured.

Granular cell myoma and schwannoma: fine structural and immunohistochemical study

We present the histological, ultrastructural, and immunohistochemical findings of two granular cell tumors of different histogenesis: a mediastinal granular cell schwannoma, and an uterine granular cell leiomyoma. Ultrastructurally the mediastinal tumor showed granular cell changes of the Schwann cells which were reactive for S-100 protein and Leu 7 antigen, but not for actin, desmin, CEA, EMA, or cytokeratin. Ultrastructural study of the uterine lesion demonstrated smooth muscle cells with only a few "autophagic" facuoles to cells nearly replaced by lysosomes. Immunohistochemically this tumor showed reactivity for actin, desmin, and Leu 7 antigen, but was S-100 protein, CEA, EMA, and cytokeratin negative.