Black lesions in the oesophagus

Introduction

A 69-year-old Trinidadian woman with a past medical history of gastro-oesophageal reflux disease (GERD) presented with a 2-week history of dysphagia. Physical examination did not reveal any cutaneous or mucocutaneous lesions. Neurological exam also was normal. There were no laboratory abnormalities. A CT scan showed circumferential wall thickening and moderate patulous proximal oesophagus without any distal oesophageal findings or abnormal findings in the chest or abdomen. A barium oesophagram revealed severe oesophageal dysmotility and GERD. Given the dysphagia and CT findings, an oesophagogastroduodenoscopy (EGD) was performed. The EGD revealed pigmented mucosa in the lower third of the oesophagus (figure 1A). Biopsy revealed melanin deposition in the basal squamous epithelium (figure 1B) with evenly spaced melanocytes, highlighted by immunohistochemistry for Melan-A and SOX10 (figure 1C).

Figure 1.

(A) Oesophagogastroduodenoscopy revealing hyperpigmented lesions in the lower third of the oesophagus. (B) Biopsy of hyperpigmented lesion revealing melanin within the basal squamous epithelium with evenly spaced melanocytes and pigmented dendritic processes (C) Immunohistochemistry of biopsy for Melan-A and SOX10, a nuclear marker of melanocytes, highlighting melanocytes without nesting or pagetoid scatter.

Question

What is this finding, and how is it managed?

Answer

Oesophageal melanocytosis is a benign melanocytic proliferation in the basal layer of the squamous epithelium.¹ The aetiology of the melanocytosis is not clear; however, it has been suggested that aberrant migration during embryogenesis and chronic irritation such as GERD could lead to its occurrence. Largely, cases have been found in Asian populations with only a few cases reported in the western countries. Endoscopically, oesophageal lesions are largely discovered in the middle and lower third of the oesophagus.² Biopsies from oesophageal melanocytosis reveal hyperpigmentation of basal epithelium with associated evenly spaced melanocytes along the basal epithelium. These melanocytes lack confluent growth or pagetoid growth and cytologic atypia—classic features of melanoma in-situ.

While the progression from oesophageal melanocytosis to melanoma has not been demonstrated, pathological evaluations of excisions of oesophageal melanoma have noted the presence of associated oesophageal melanocytosis, suggesting that melanocytosis may represent a prerequisite to melanoma in some circumstances.³

The uncertainties described above, in combination with reports of melanocytosis mimicking esophageal melanoma,⁴ stress the need for close endoscopic monitoring and in some cases where suspicion is high surgical resection. For this case, the patient was managed symptomatically for her GERD and dysphagia with a planned follow-up EGD in 1 year.