Solitary CD8-Positive Primary Cutaneous Peripheral T-Cell Lymphoma: A Question of Classification

Area of Science:

• Dermatopathology
• Hematopathology
• Oncology

Background:

• Acral CD8(+) lymphoma is a provisional entity in the WHO Lymphoma Classification.
• It is characterized by a specific dot-like CD68 immunohistochemical expression.
• This entity is typically associated with acral (extremity) skin sites.

Observation:

• A solitary, ulcerated cutaneous lesion on the forehead of an adult male was analyzed.
• The lesion exhibited a CD8(+) cytotoxic phenotype.
• Areas of dot-like CD68 positivity were observed, mimicking acral CD8(+) lymphoma.

Findings:

• The forehead location and other features deviated from the classical description of acral CD8(+) lymphoma.
• Immunohistochemical analysis revealed a CD8(+) cytotoxic T-cell phenotype.
• The pattern of CD68 positivity, while dot-like in areas, was not entirely typical.

Implications:

• The case highlights diagnostic challenges in cutaneous lymphomas.
• It suggests that similar immunohistochemical findings can occur in non-acral sites.
• The preferred diagnosis of peripheral T-cell lymphoma, not otherwise specified, broadens the differential diagnosis for such lesions.