Giant congenital naevus on back

Dr Veronique Bataille and Dr Paul Nathan
Mount Vernon Cancer Centre
Northwood, Middlesex, UK 

This 77 year old lady presented to her GP with a chronic cough and fatigue. A chest X-ray revealed a large tumour in left upper lobe pushing the trachea. The following CT scan showed a 75 x 42 mm mass in the left upper lobe with enlarged pre-carinal lymph nodes displacing the trachea. Multiple liver metastases were also noted. On examination, she had a giant congenital naevus covering half of the torso as well as multiple congenital naevi of smaller size on the face and limbs. She had skin type 4 and was non Caucasian. Her brother died many years ago after being diagnosed with a nasal melanoma in his thirties although the histology has not been verified as the records dated back to the mid-1970s. The biopsy of the lung tumour showed melanoma cells with positive immunohistochemistry. BRAF status was negative. The giant congenital naevus on the back had showed new areas of hypopigmentation which could have been an immune reaction to the local melanocytes after the onset of the lung melanoma. However, areas of hypopigmentation are not unusual in large congenital naevi. It is possible that this case represents a primary melanoma of the lung in view of the well demarcated tumour in the upper lobe but primaries are extremely rare in the lung. It could also be a case of unknown primary presenting late with lung and liver metastases. The patient was offered immunotherapy but passed away shortly after presenting to the melanoma  clinic. 

Figure 1. Giant congenital naevus on back with areas of regression