Primitive Neuroectodermal Tumour of Subcutaneous Tissue Presenting as a Shoulder Lump: A Case Report

Area of Science:

• Oncology
• Pathology
• Radiology

Background:

• Primitive neuroectodermal tumours (PNETs) are rare, poorly differentiated small round cell neoplasms, predominantly affecting children.
• Peripheral PNETs are less common than central types and often mimic soft tissue sarcomas.
• Subcutaneous PNETs are exceptionally rare, with limited documented cases, primarily in the anterior abdominal wall.

Observation:

• This report describes a unique case of a peripheral PNET originating in the subcutaneous tissue of the right shoulder.
• The patient was a young adult, an age group where PNETs are seldom observed.
• Magnetic resonance imaging (MRI) was utilized for diagnostic evaluation.

Findings:

• The tumour presented as a subcutaneous lesion in the shoulder region.
• Histopathological analysis and immunohistochemistry, including neuron-specific enolase (NSE) staining, confirmed the diagnosis of PNET.
• This represents the first reported instance of a PNET in the subcutaneous tissue of the shoulder.

Implications:

• This case expands the known anatomical distribution of peripheral PNETs.
• It highlights the importance of considering PNETs in the differential diagnosis of adult subcutaneous soft tissue masses.
• Further research may elucidate the specific characteristics and optimal management strategies for PNETs in unusual locations.