LYP Type C | Dermatopathology

Final diagnosis: Borderline Type-C Lymphomatoid Papulosis.

Diagnosis comment: The biopsy shows a highly atypical transformed neoplastic CD4-positive, CD30-positive angiocentric and superficial diffuse atypical lymphocytic infiltrate of the alpha beta subset. The CD4 positive T-cells also exhibit cytotoxic protein expression, given the degree of immunoreactivity for granzyme and TIA. Not surprisingly there is a variable reduction in staining for select pan T cell markers namely CD3, CD5, and CD7. The overlying epidermis exhibits a pustular psoriasiform diathesis.

Overall, the distinct clinical presentation, along with this histopathology and phenotypic profile is very characteristic for a lymphomatoid papulosis as a form of indolent CD30 positive lymphoproliferative disease. The extent of large cell infiltration would fall under the rubric of borderline type-C lymphomatoid papulosis. In theory, the lesions should undergo spontaneous regression without any therapeutic intervention.

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Slide 1: The patient developed a papular skin rash recently. It is asymptomatic. There is a total of 15 lesions.

Slide 2: The biopsy shows a very atypical mononuclear cell infiltrate within the dermis in association with an epidermis that exhibits a psoriasiform hyperplasia with extensive permeation by neutrophils including neutrophil imbued parakeratosis. The infiltrate within the dermis is interstitial and angiocentric, although superficially the infiltrate does assume a band-like pattern.

Slide 3: The cells are in the 15 to 20-micron range. They show round-oval nuclei with an open chromatin and conspicuous eosinophilic nucleolation.

Slide 4: The cytoplasms are moderately abundant and lightly eosinophilic in quality.

Slide 5: Although the cells are severely atypical, there is an element of monotypism to the neoplastic cells. Scattered mitotic figures are noted as well.

Slide 6: The atypical lymphocytes are of the CD4 subset.

Slide 7: Only a few reactive smaller CD8 positive staining T-cells are present. Not shown: There is extensive highlighting of the infiltrate for the pan T-cell markers CD2. A number of the lymphocytes stain for CD3, although relative to CD2 the extent of immunoreactivity qualitatively and quantitatively is less with the estimated reduction being around 20-30%. A CD5 stain highlights a few cells very intensely but the large neoplastic cells either are not staining or show a weaker and/or partial cytoplasmic membrane pattern. The CD7 highlights small reactive lymphocytes. The CD79a stain is negative primarily.

Slide 8: There is extensive cytoplasmic membrane and Golgi staining for CD30 with the large neoplastic cells demonstrating a very strong pattern of immunoreactivity.