ALK Positive Non-Neural Granular Cell Tumour in Two Paediatric Patients- A Case Report

Non-neural granular cell tumour (PNNGCT) is a rare mesenchymal neoplasm of unknown lineage with prominent cytoplasmic granularity [1].These tumors are more common in children and young adults, and commonly involve the back and extremities.A panel of immunostains is important to rule out other differential diagnoses.In contrast to conventional granular cell tumor (GCT), NNGCT lacks S100 expression, hence, NKI-C3 and anaplastic lymphoma kinase (ALK) stains can be particularly helpful in confirming the diagnosis.In addition, an underlying ALK gene rearrangement has been reported in a small subset of cases [2].In general, most of these tumors appear to behave in a benign fashion, and conservative management is recommended.Our results demonstrate that NNGCT harbour ALK fusions, which suggests that NNGCT are molecularly diverse, and further substantiate NNGCT as distinct from GCT [3].