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Pinpoint papular variant of polymorphous light eruption: clinical and pathological correlation
1Department of Pathology, Henry Ford Hospital, Detroit, MI 48202, USA. ilabansal@yahoo.com
Summary
Polymorphous light eruption (PMLE) has a distinct pinpoint papular variant with unique histology in acute and subacute phases. This variant can be differentiated from lichen nitidus based on its histological and immunophenotypic characteristics.
Area of Science:
- Dermatology
- Immunohistochemistry
- Histopathology
Background:
- Polymorphous light eruption (PMLE) is a common photodermatosis.
- It presents with various morphological variants, including a pinpoint papular type.
Observation:
- A study examined 10 patients with pruritic pinpoint papular eruption linked to sun exposure.
- Skin biopsies and immunohistochemistry were performed to analyze histology and immunophenotype.
Findings:
- Acute phase: pinpoint papules/vesicles with spongiosis, edema, and lymphocytic infiltrate.
- Subacute phase: pinpoint papules with nodular lymphocytic/histiocytic collections and epidermal changes.
- Immunohistochemistry showed CD8 and CD68 positivity, variable CD4, and S-100 negativity.
Implications:
- The pinpoint papular variant of PMLE is a distinct entity with characteristic histology.
- Histological and immunophenotypic analysis aids in differentiating this PMLE variant from lichen nitidus.
