Asymptomatic Nodular Lesion Over the Neck in an Old Woman.

Clinical Findings

A 56-year-old woman presented with an 8-month history of single, asymptomatic nodule over the neck, which was progressively increasing in size. The patient was systemically well. On examination, there was a single firm nodule of size 2.5 × 3.5 cm over the right lateral aspect of the neck. The nodule was dark brown in color and was fixed to the overlying skin. The lesion had a lobulated appearance with a zone of erythema at the periphery [Figure 1]. An excision biopsy was performed to reach a diagnosis.

Figure 1

Single firm nodule over the neck with overlying thick skin giving a lobulated appearance and a zone of erythema at the periphery

Histopathologic Findings

Hematoxylin and eosin stain of the tissue showed diffuse infiltration of the dermis with uniform looking cells. The cells had centrally located nuclei and granular eosinophilic cytoplasm. There was no significant nuclear atypia or mitotic activity [Figure 2a and b]. The excised margin was free from tumor. Immunohistochemistry with S100 revealed a strong positive staining [Figure 2c].

Figure 2

Hematoxylin and eosin stain: (a and b) (×40) showed diffuse infiltration of the dermis with uniform looking cells. These cells had centrally located nuclei and granular eosinophilic cytoplasm. There was no significant nuclear atypia or mitotic activity. (c) (×40): Immunohistochemistry with S100 revealed a strong positive staining

Answer

Granular cell tumor.

Discussion

Granular cell tumor (GCT) is a rare neoplasm that originates from Schwann cells and is a slowly growing, usually solitary, asymptomatic, smooth-surfaced nodule located in submucosal, intradermal, or subcutaneous region. It is commonly seen during the 3rd to 5th decades of life but can occur at any age with a female preponderance. GCT most commonly affects the head and neck region, which accounts for 45% to 65% of all sites affected by tumour. Of this, 70% are located in the oral cavity, especially the tongue, buccal mucosa and hard palate. Other commonly affected areas are skin and subcutaneous tissues (30%), breast (15%), respiratory (10%) or gastrointestinal tracts, and the biliary system.[1] Multifocal involvement has been reported in 10–25% of the cases.[2] Multiple GCT can occur as an isolated disorder or might be part of the LEOPARD syndrome, Noonan syndrome, neurofibromatosis, and Watson syndrome.

Histologically, it is characterized by large polyhedral cells containing mildly eosinophilic, uniform fine to coarse granules. This granular appearance is the result of dense cytoplasmic lysosomes. These granules stain positively with Periodic acid-Schiff (PAS) and are diastase resistant. Occasionally, spread along the peripheral nerves and vascular channels or infiltration of arrector pili can be seen.[3] On immunohistochemical analysis, GCT shows positivity to a broad panel of antibodies. S100 and CD68 are most commonly used immunohistochemical stains, other positive markers include neuron-specific enolase, nerve growth factor receptor 5, inhibin alpha, protein gene product 9.5, p75, vimentin, calretinin, and microphthalmia-associated transcription factor.[4]

Clinically, various benign tumors including lipoma, dermatofibroma, xanthogranuloma, leiomyoma, neurofibroma, adnexal tumors, and schwannoma can mimic GCT, but they can be differentiated by histopathological and immunohistochemical features.[5]

GCT is usually a benign tumor, occasionally it may be locally aggressive. Less than 2% are malignant and are associated with a poor prognosis.[5] The most common metastatic sites are regional lymph nodes, lungs, liver, and bones. Surgical excision of the tumor remains the mainstay of therapy.

Declaration of patient consent

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Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.