|Year : 1990 | Volume
| Issue : 6 | Page : 441-442
Granular cell myoblastoma
V Laxmi Nair, MP Binitha
V Laxmi Nair
Source of Support: None, Conflict of Interest: None
A case of granular cell myoblastoma in a twenty four year old lady is reported.
Keywords: Granular cell myoblastoma
|How to cite this article:|
Nair V L, Binitha M P. Granular cell myoblastoma. Indian J Dermatol Venereol Leprol 1990;56:441-2
Granular cell myoblastoma is a benign tumor of the skin and internal organs. The conditions was first described by Abrikossoff, and the name granular cell myoblastoma was suggested by Horn and Stout. It is a relatively uncommon condition and in spite of extensive clinical and pathological investigations including electron microscopic and histochemical studies, the histogenesis is controversial.
| Case Report|| |
A 24 year - old lady came for pruritic nodular lesions over the trunk and arms of 6 months duration. She had a skin coloured nodule on the abdomen initially, which gradually increased in size and developed a brownish tint. Similar lesions appeared later on the trunk and arms. There were five nodules varying from 2 to 4 centimeters in diameter. The consistency was firm to hard and they were fixed to the overlying skin. There was no family history of similar lesions. General and systemic examination were within normal limits. A clinical diagnosis of mycosis fungoides, tumour d' emblee type was made. Routine hematologic examination, urine analysis, serological test for syphilis and x ray of the chest were normal.
Biopsy from a nodule showed mild hyperkeratosis with minimal irregular acanthosis. There was a tumour in the mid dermis extending to the subcutaneous tissue. The tumour cells were large, elongated cells with pale cytoplasm filled with faintly staining eosinophilic coarse granules. The nuclei were small and centrally located. Some of the cells had more than one nucleus and occasional mitotic figures were observed. The tumor cells were arranged in clusters surrounded by collagen strands. The granules were PAS positive diastase resistant.
| Comments|| |
Granular cell myoblastoma, though it may occur at all ages, is most common during the third to fifth decade. The tumor is usually solitary and asymptomatic. In 10% of cases it may be multiple. It has been reported to be pruritic at times. Our patient, too, had mild pruritus. Some patients may complain of a dull, paroxysmal pain.
In addition to the skin and subcutaneous tissue, it may involve the tongue, alveolar process, breast, larynx, upper gastrointestinal tract, respiratory tract, orbit, female anogenital region and pituitary stalk. It's clinical features are not characteristic and only the histopathological examination of a nodule establishes the diagnosis.
The tumor was thought to be composed of immature striated muscle cells or myoblasts, and hence the name granular cell myoblastoma. Electron microscopic and histochemical studies have shown that myoblasts are not the cells of origin. Some considered them as histiocytic collections, but this is now considered unlikely, because the tumor cells lack specific histiocytic markers such as lysozyme and alpha-one antitrypsin. A Schwann cell origin is postulated, because of the tumor's frequent association with peripheral nerves, and electron microscopic appearance of a basal lamina around cells, and cytoplasmic inclusions reminiscent of degenerated myelin.
The presence of granular cytoplasm aids in differentiating granular cell myoblastoma from xanthoma, fibroma, rhabdomyoma and rhabdomyosarcoma. Squamous cell carcinoma may occasionally show granules but they are PAS negative. The overlying epidermis frequently shows pseudo-epitheliomatous hyperplasia. This should not be mistaken for squamous cell carcinoma. Malignant degeneration may rarely occur and there may be extensive metastasis to skin, skeletal muscle and viscera.
The only effective treatment is excision. Radiotherapy and chemotherapy have no place in the treatment.
| References|| |
|1.||Funan HU : Granular cell myoblastoma, in: Clinical Dermatology, 12th revision, Editors Demis DJ and McGuire J : Harper and Row Publishers, London, 1982; Vol 4, Unit 26-2, pp 1-5. |
|2.||Apisarnthanarax P : Granular cell tumor (review), J Amer Acad Dermato!, 1981; 5: 171-182. |
|3.||Fisher ER and Wechsler H : Granular cell myoblastoma-a misnomer, Cancer, 1962; 15: 936954. |
[Figure - 1], [Figure - 2]