Multiple granular cell tumour

[Multiple granular cell tumours in a patient with Noonan's syndrome and juvenile myelomonocytic leukaemia]

BACKGROUND

Granular cell tumour (GCT) is a rare form of tumour comprising Schwann cells. Herein, we report a case of a child presenting Noonan syndrome complicated by juvenile myelomonocytic leukaemia (JMML) and who also developed a multiple form of GCT. We discussed the molecular mechanisms that might account for this association.

PATIENTS AND METHODS

A six-year-old boy with Noonan syndrome complicated by JMML presented three asymptomatic subcutaneous nodules on his back, forearm and neck. Histological analysis revealed GCT. A literature review revealed seven cases of Noonan syndrome presenting GCT, none of which were associated with JMML. Mutation of gene PTPN11, via hyperactivation of intracellular Ras signalling may cause the development of GCT and JMML in children presenting Noonan syndrome.

DISCUSSION

Detailed clinical examination is recommended in children presenting GCT to screen for multiple forms and for signs of malformation suggestive of a genetic syndrome. Ours is the first case to be described of Noonan syndrome complicated by JMML associated with multiple GCT. This association once again raises the important question of the role of the Ras-MAPK signalling pathway in the development of benign and malignant tumours of solid organs or blood, associated with genetic syndromes.

[Childhood cutaneous Abrikossoff tumor]

INTRODUCTION

Granular cell tumor (GCT), also known as Abrikossoff tumor, is a rare and benign neoplasm that more commonly affects the oral cavity in adults. We report here 2 childhood cases of a cutaneous granular cell tumor.

CASE REPORTS

An 8- and a 12-year-old girl, with no past medical history, presented with pigmented nodular lesions located, respectively, in the left scapular region and the left iliac crest. Histological examination showed sheets and clusters of infiltrating tumor cells with morphologic and immunohistochemical features consistent with granular cell tumor. In both cases, the lesions were excised with 2-cm margins. The patients are presently being reviewed at 6-month and 2-month intervals to evaluate for recurrence and any malignant transformation. They were in good health with no signs of further tumor development.

DISCUSSION

GCT is a relatively uncommon benign neoplasm probably of neural origin derived from Schwann cells. The tongue and buccal mucosa are commonly affected. It develops between the second and sixth decades of life, more frequently among women and blacks. It can also occur in childhood, but this is rare. The cutaneous forms, as in the present observations, are exceptional. Benign granular cell tumours are generally seen as a solitary asymptomatic nodule less than 3 cm in size involving the subcutaneous or submucosal tissues. Histologically, the tumor is not encapsulated but is well circumscribed. The tumor cells may show a degree of infiltration of the surrounding connective tissue. The cells are polygonal, have abundant cytoplasm, are granular and weakly eosinophilic. The nuclei are small, vesicular, and highly chromatic. Mitotic figures are rare. A key element for the histological diagnosis is the expression of S100 protein, neuron specific enolase (NSE), and vimentin on immunohistochemistry. The treatment of choice is a conservative surgical excision of the lesion. However, as the GCT has a poorly defined margin, it is suggested that the tumor should be excised along with portions of adjacent tissue. A low rate of recurrence of the lesion has been reported.

CONCLUSION

The specific value of these rare cases is the occurrence in 2 children and the cutaneous location.

Granular cell tumor of the scrotum in a child with Noonan syndrome

Granular cell tumor is a rare neoplasm thought to be of neural origin, composed of cells with distinctive granular cytoplasm. Granular cell tumors most often arise on the tongue, but can occur at any body site, and therefore initial presentation to dermatologists is common. We report a granular cell tumor of the scrotum in a child with Noonan syndrome, known to have a mutation in the PTPN11 gene. No previous reports of granular cell tumor of the scrotum in a child are found. The tumor is usually benign; however, it can have a high local recurrence rate (variable between 2% and 50% dependent on whether initial excision is complete and on the occurrence of an infiltrative growth pattern) and therefore long-term follow-up is necessary. This case highlights the occurrence of granular cell tumor, a diagnosis not to be missed by the dermatologist. In addition, we postulate the possible role of PTPN11 mutations in the development of granular cell tumor.

Multiple plaques on the back: S-100 negative benign granular cell tumor

Granular cell tumor is a rarely seen disease characterized by a gradually developing nodular lesion, which is difficult to diagnose. It has been thought to originate from Schwann cells. The tumor usually appears in the 4th-6th decades of life, more frequently in women and blacks, and has a multifocal location in 10-25% of the cases. The malignancy potential is 1-3%, with 70-74% of the cases in women. Ninety-eight percent of the cases are S-100 positive. The present paper describes an 18-year-old female patient with benign granular cell tumor. This rarely seen type of tumor was S-100 negative and has been detected in biopsies taken from multiple asymptomatic plaques and maculopapular lesions. They were 0.5-4 cm in diameter, light brown in color, and with clear contours and had been gradually growing on her back the last nine years.