p53 oncoprotein expression in cutaneous lymphoproliferations.

BACKGROUND AND DESIGN: p53 overexpression has been reported in systemic lymphoproliferations, but our study is the first large series, to our knowledge, dealing with p53 expression in primary cutaneous lymphomas. p53 immunohistochemical detection using DO7 monoclonal antibody was performed in 54 cutaneous lymphoproliferative disorders, including 37 primary cutaneous T- or B-cell lymphomas. RESULTS: No expression of p53 was found in 14 mycosis fungoides and seven pleomorphic T-cell lymphomas of either low or high grade of malignancy. Furthermore, no p53-positive cells were shown in low-grade B-cell lymphomas and in benign chronic dermatoses. p53 overexpression was seen over lymphomatous cells in 10 cutaneous lymphomas of high grade of T- or B-cell origin with two immunoblastic, three centroblastic, and five anaplastic lymphomas. Five of them occurred in human immunodeficiency virus-infected individuals, suggesting a possible interaction between p53 and viral proteins. p53 immunoreactivity was found over Reed-Sternberg-like cells in two cases of lymphomatoid papulosis. A labeling of keratinocytes located mainly in basal cell layers of the epidermis was observed in only five cases regardless of the lymphoma histologic subtype. CONCLUSIONS: p53 overexpression was not found in the most frequent primary cutaneous lymphomas, epidermotropic T-cell lymphomas. Alternatively, p53 immunoreactivity was observed in most primary cutaneous lymphomas of high grade of malignancy occurring in individuals either infected or not infected by human immunodeficiency virus. Molecular studies will determine if p53 overexpression is associated with p53 gene alteration and help to understand the role of p53 in primary cutaneous lymphoma genesis.

Ki-1-positive large-cell cutaneous lymphoma mimicking a Stewart-Treves angiosarcoma.

Anaplastic large-cell cutaneous lymphomas (ALCL) represent a heterogeneous group. Primitive cutaneous lymphomas are exceptional, sometimes with a deceptive clinical aspect, but must be considered as a distinct clinicopathologic entity. We report a case of a cutaneous ALCL, appearing 7 years after a homolateral Hodgkin ganglionic lymphoma and occurring on a chronic lymphoedema of the arm. A Stewart-Treves angiosarcoma was suggested owing to its location, vascular aspect and low histologic differentiation. Immunohistochemistry was helpful in making the diagnosis of ALCL. Southern blotting analysis revealed a rearrangement of the beta-chain of the T-receptor gene, thus suggesting the T-cell origin of this lymphoma.

Peripheral neuropathies and lymphoma without monoclonal gammopathy: a new classification.

Recent progress in immunopathological studies of peripheral nerve and lymph node fragments together with 16 personal cases and numerous clinicopathological reports have suggested a new classification of peripheral neuropathies (PN) and lymphomas. These are: (1) PN due to local infiltrations by a T-cell lymphoma: (2) acute polyradiculoneuritis due to active demyelination and associated with infiltrates of a T-cell lymphoma in the epineurium, resembling Marek's disease (which is a T-cell lymphoma); (3) B-cell lymphoma proliferation which may be restricted to or predominate in the peripheral nervous system, with a large clinicopathological heterogeneity ranging from localized forms to ascending polyradiculoneuropathies; (4) angiotropic lymphoma, which is a B-cell lymphoma and may present as an acute mononeuropathy; (5) patients with acquired immunodeficiency syndrome due to lymphomatous infiltrates in the endoneurium, of which 2 cases of PN have been reported; (6) PN associated with organomegaly, endocrinopathy, M-component and skin lesions, certain cases being associated with a plasmocytoma and sometimes Castleman's disease but without any monoclonal gammopathy: (7) classic Guillain-Barré syndrome, prone to develop in patients with extraneural lymphoma but without any lymphomatous infiltrates in the peripheral nervous system; (8) certain cases (4 out of 16 in our series) where there is no clear relationship between PN and lymphoma, and there are mainly features of axonal degeneration. Inflammatory perivascular infiltrates were sometimes present in the epineurium.