Relapsing eruptive multiple Spitz nevi or metastatic spitzoid malignant melanoma?

Area of Science:

• Dermatopathology
• Oncology
• Genetics

Background:

• Spitz nevus (SN) is a melanocytic proliferation that can clinically mimic malignant melanoma.
• Pseudohypoparathyroidism is a rare genetic disorder affecting calcium and phosphate metabolism.

Observation:

• A patient with pseudohypoparathyroidism presented with a single Spitz nevus.
• The lesion relapsed twice as multiple agminated lesions, maintaining the original histological features of Spitz nevus.
• The recurrent lesions were initially misdiagnosed as metastatic malignant melanoma at another institution.

Findings:

• Histopathological examination confirmed the lesions were recurrent Spitz nevi, not melanoma metastasis.
• The clinical presentation of multiple relapsing Spitz nevi in the context of pseudohypoparathyroidism is highly unusual.

Implications:

• This case highlights the critical importance of precise histopathological assessment for differentiating Spitz nevi from malignant melanoma.
• Accurate diagnosis is essential to prevent misdiagnosis and avoid potentially harmful and unnecessary therapeutic interventions for benign lesions.
• Understanding rare presentations of Spitz nevi in patients with genetic disorders like pseudohypoparathyroidism may improve diagnostic accuracy.