Granular cell myoblastoma: an immunoperoxidase study using a variety of antisera to human carcinoembryonic antigen

Benign Granular Cell Tumor of the Breast: A Misleading Disease

Granular cell tumor (GCT) is a relatively rare neoplasm, and almost always benign in its prognostic behavior. Location of this tumor in the breast presents serious problems for differential diagnosis, both from a clinical point of view and at gross pathological examination, because of its resemblance to carcinoma. Fine needle aspiration biopsy and intraoperative frozen section examination may not be of any further help. The histogenesis of these lesions has been widely debated in the past, but no universally accepted conclusion has been reached. Most GCTs appear to be derived from Schwann cells, but many different neoplastic and non-neoplastic lesions show granular cell changes. Therefore, GCT should not be considered as a single entity but as the result of a cytoplasmic change due to still unknown metabolic alterations that may occur in various cell types. No firm conclusions can be drawn regarding the suspected hormonal influence on the development of breast GCT.

The authors describe three typical cases of breast GCT that occurred in patients of different ages, and discuss the most important questions concerning this lesion.

Expression of inhibin-alpha by granular cell tumors of the gallbladder and extrahepatic bile ducts

This is the first report of inhibin-alpha expression in granular cell tumors. A Medline search of the literature revealed no case reports of granular cell tumors in any location of the body being tested for inhibin-alpha immunohistochemically, by enzyme-linked immunosorbent assay, by radioimmunoassay, or by immunoprecipitation. Seventeen cases of previously diagnosed granular cell tumors of the gallbladder and extrahepatic bile ducts with hematoxylin and eosin-stained sections, and S-100 protein immunostain were retrieved from the archives of the Armed Forces Institute of Pathology. All cases were reviewed for diagnostic accuracy and then immunostained for inhibin-alpha (with endogenous biotin blocking). All 17 (100%) cases were diffusely positive for inhibin-alpha immunostain. Previous studies of inhibin-alpha-positive lesions reported in the literature include sex cord stromal tumors (granulosa cell tumors, luteinized thecomas, Leydig cell tumors), placental and gestational trophoblastic lesions, and adrenal cortical tumors. This study adds the granular cell tumor to the list of inhibin-positive lesions and should prove helpful in differential diagnosis of these lesions.

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.

Granular cell tumour of the breast

Eight cases of benign granular cell tumour of the breast are reported. Seven patients were women and one was male. The age at the time of the excision ranged from 17 to 73 (average 40.1) years. All tumours were positive for S-100 protein and negative for keratin, myoglobin and gross cystic disease fluid protein. In two cases ultrastructural studies revealed findings identical to those in the previously reported cases of granular cell tumours. None of these cases were diagnosed preoperatively. In six cases the clinical and mammographic findings, and in one case the frozen section, led to an erroneous diagnosis of malignancy. The clinico-pathological features of the cases are delineated in order to draw attention to a benign condition which closely simulates malignancy.

A desmoplastic granular cell tumour of the oral cavity: report of a case

A case of granular cell tumour of the buccal mucosa demonstrating marked desmoplasia is presented. The bulk of the tumour is composed of dense collagenous stroma, which surrounds isolated nests of tumour cells. Since the histomorphologic appearance of this variant is different from that usually seen in this lesion, the diagnosis is supported by immunohistochemical demonstration of S-100 and Vimentin in the tumour cells. The authors believe that this case represents the first report of a desmoplastic granular cell tumour of the oral tissues.

Multiple granular cell tumors of the palate

A report of a case of bilateral granular cell tumors of the soft palate is presented. This is an unusual location for the tumor and is the first report of bilateral tumors at this site.

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.

Granular-cell tumours of the skin do not express carcino-embryonic antigen

Granular-cell tumour (GCT) of the skin is an uncommon tumour of disputed histogenesis, that has been subjected to several immunohistochemical studies. The controversy existing in the literature concerning the expression of carcinoembryonic antigen (CEA) by GCT prompted us to study a series of 17 cases of cutaneous GCT by using an avidin-biotin-immunoperoxidase technique on routinely-processed tissue sections. No CEA activity was detected in any of the tumours screened. The reasons for this controversy are discussed.

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

We report a unique angiosarcoma of the skin of the face in which a large part of the tumour was of granular cell appearance. Histologically the granular cells resembled those of conventional granular cell tumours. By electron microscopy the granules were identical to those of granular cell tumours but other features were lacking. Stains for vimentin and factor VIII related antigen were positive, but for S-100 protein and CEA were negative. The occurrence of granular cell change in an angiosarcoma supports the view that granular cell tumours are histogenetically diverse.

Thyroid-associated antigens in routinely embedded carcinomas. Possibilities and limitations studied in 116 cases

Routinely embedded tumors (116 cases) were screened immunohistochemically for the thyroid-associated antigens, thyroglobulin and calcitonin, and for carcinoembryonic antigen (CEA). Also the influence of different fixatives, decalcification, and embedding procedures were studied. All follicular and papillary carcinomas stained positive for thyroglobulin; 14 of the 23 undifferentiated carcinomas showed only a focal and weak reaction for thyroglobulin. The metastases showed the same reaction pattern as the primary lesion. Calcitonin was present only in the medullary carcinomas and in 2 of the 23 undifferentiated carcinomas. Carcinoembryonic antigen was not present frequently in the investigated carcinomas. The reliability of the method, its clinical importance, and the possibilities it offers for a more precise classification are discussed. The diagnostic value of the method is illustrated by two case reports.

Influence of decalcifying agents on immunoreactivity of formalin-fixed, paraffin-embedded tissue

The influence of eight decalcifying agents on the immunoreactivity of formalin-fixed, paraffin-embedded tissue for immunoglobulins, lysozyme, factor VIII-related antigen and keratin was studied using the unlabelled antibody peroxidase-antiperoxidase (PAP) method. Limited studies were also performed on tissues fixed in acid-formalin mixtures. All tissues were stained using an indirect immunoperoxidase method with mouse monoclonal antibodies to IgM, kappa and lambda light chains. The results suggest that, with controlled trypsinization of sections, it was possible to obtain optimal immunostaining for all tested antigens, with adequate preservation of histological structure, after decalcification in neutral EDTA or 10% aqueous acetic or formic acid. Tissue treated with agents containing mineral acids exhibited variable immunoreactivity and impaired counterstaining.

Ultrastructure of poorly differentiated diffuse epithelial mesotheliomas

In differentiating diffuse epithelial mesothelioma from metastatic adenocarcinoma in pleural and peritoneal biopsies, the number and form of microvilli and the amount and distribution of tonofilaments are thought to be the most useful criteria. This report details 5 cases of diffuse epithelial mesothelioma in which the characteristic fine structural features of neoplastic mesothelial cells were markedly modified. The majority or all tumor cells were poorly differentiated in electron micrographs, particularly with reduced prominence or absence of intermediate filaments, desmosomes, intracytoplasmic lumina, and microvilli. Immunohistochemistry revealed the absence of carcinoembryonic antigen and the presence of cytokeratin in all cases. Comparison with a better differentiated case suggests cytologic details that are useful in distinguishing the poorly differentiated type of epithelial mesotheliomas from adenocarcinoma. These include a mosaic pattern of closely associated tumor cells with a few long, narrow cytoplasmic processes lying parallel to adjacent plasma membranes, abundant cytoplasm with limited organelles usually having a polar arrangement, and nuclei with markedly disaggregated chromatin and prominent nucleolonemal-type nuclei.