Pathology of Lymphomatoid Papulosis
A chronic recurrent skin disease characterized by waxing and waning papules and nodules.
Lymphomatoid papulosis (LyP) is a recurrent hemorrhagic papular skin eruption with a clinically benign course and histopathologic features of lymphoma.
The lesions usually present as papules and nodules that spontaneously involute.
Initially the lesions are smooth but later these lesions become crusted, ulcerated and necrotic.
Lymphomatoid papulosis can only be diagnosed accurately through a careful history in which the characteristic waxing and waning of the skin lesions is identified and through proper communication between clinicians and pathologists.
Age: Usually occurs in the third and fourth decade of life. This lesion may also occur in children.
Site: Trunk ; Proximal parts of the limb ; face ; scalp ; palms and sole.
LyP Type A ; LyP Type B ; LyP Type C ; LyP Type D
LyP Type A : Wedge-shaped, superficial and deep mixed infiltrate of small lymphocytes, abnormal lymphocytes and, often, plasma cells, neutrophils, and eosinophils ; Abnormal lymphocytes with large pleomorphic nuclei ; Binucleate abnormal lymphocytes that resemble Reed-Sternberg's cells and multinucleate abnormal lymphocytes; There is no epidermotropism. The term "Chunks of Coal" has been used to describe the cells with large, dark, hyperchromatic nuclei.
LyP Type B : Perivascular or band like dermal infiltrate; Small to medium sized lymphocytes with cerebriform nuclei; There is epidermotropism. (Features resemble plaque stage mycosis fungoides).
LyP Type C : Monotonous population of large atypical cells ; There are fewer inflammatory cells. (Features resemble ALCL).
LyP Type D : Recently, a further variant simulating histologically an aggressive epidermotropic CD8 positive T-cell lymphoma was described, which was named LyP type D by the authors. A case has been reported which showed an infiltrate of atypical lymphoid cells extending throughout the dermis with massive epidermotropism displaying a pagetoid reticulosis-like pattern and a CD8 (+) CD30(+) cytotoxic T-cell phenotype. This cytotoxic variant of LyP may be histopathologically indistinguishable from primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma, and may be the source of pitfalls in the diagnosis and classification.
Differentiating between mycosis fungoides and anaplastic large cell lymphoma and Hodgkin's disease may be very difficult.
Mycosis fungoides consists of abnormal lymphocytes that may be identical to those of lymphomatoid papulosis, but infiltrates tend to be bandlike, not wedge-shaped. No neutrophils are present as a rule in mycosis fungoides.
Lesions of Hodgkin's disease usually do not display a wedge-shaped infiltrate and exhibits Reed-Sternberg's cells consistently.
Clinical, microscopic and immunohistochemical features of lymphomatoid papulosis and anaplastic large cell lymphoma (ALCL) may overlap.
Both Primary cutaneous CD30-positive ALCL and lymphomatoid papulosis are characterized by CD30-positive large atypical cells predominantly of T-cell origin.
Insect bites exhibit a wedge-shaped infiltrate composed of lymphocytes and eosinophils. Slightly abnormal lymphocytes may be present but these are not in mitosis.
Pityriasis lichenoides et varioliformis acuta is also included in the differential diagnosis.
In all cases clinicopathologic correlation is necessary to establish an accurate diagnosis and for an adequate management of these patients.
Lymphomatoid papulosis type D: a newly described variant easily confused with cutaneous aggressive CD8 -positive cytotoxic T-cell lymphoma.
A variant of lymphomatoid papulosis simulating primary cutaneous aggressive epidermotropic CD8 positive cytotoxic T-cell lymphoma. Description of 9 cases.
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