Mf. Baldassano et al., Cutaneous lymphoid hyperplasia and cutaneous marginal zone lymphoma - Comparison of morphologic and immunophenotypic features, AM J SURG P, 23(1), 1999, pp. 88-96
Citations number
29
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
Cutaneous marginal zone lymphoma (MZL) is a recently described low-grade B-
cell lymphoma that usually follows an indolent course. This tumor shares ma
ny histologic and clinical features with cutaneous lymphoid hyperplasia (CL
H), a benign reactive lymphoid proliferation. Sixteen biopsy specimens from
14 patients with CLH were studied, and compared with 16 cases of cutaneous
MZL (9 primary cutaneous, 7 with secondary involvement of the skin) to det
ermine whether there were features that would permit their distinction on r
outinely fixed, paraffin-embedded tissue sections. Both disorders showed a
female preponderance (CLH: 9 F, 5 M; MZL: 11 F, 5 M). The median age was al
so similar (CLH: 54 years; cutaneous MZL: 55 years). CLH was most common on
the arm (8) and the head and neck (7) but also involved the trunk (1); pri
mary cutaneous MZL most often involved the limbs (3), trunk (3), and head a
nd neck (3). Lymphoma did not develop in any of the 14 CLH patients (follow
-up ranging from 9 to 246 months, mean 62 months). Six of 9 patients with p
rimary cutaneous MZL and all 7 patients with secondary cutaneous MZL experi
enced relapses, most commonly isolated to skin or a subcutaneous site. On h
ematoxylin-eosin stained sections, a diffuse proliferation of marginal zone
cells (p < 0.0001), zones of plasma cells (p = 0.01). the absence of epide
rmal change (p = 0.01), reactive germinal centers (p = 0.03), and a diffuse
pattern of dermal or subcutaneous infiltration (p = 0.03) were more often
seen in cutaneous MZL. A dense lymphocytic infiltrate, bottom-heavy or top-
heavy growth pattern, eosinophils, and a grenz zone were seen equally often
in both disorders. Dutcher bodies were observed only in cutaneous MZL. Imm
unoperoxidase stains on formalin-fixed paraffin-embedded tissue sections sh
owed monotypic expression of immunoglobulin light chains by plasma cells in
11 of 16 MZL cases. By definition, no case with monotypic plasma cells was
diagnosed as CLH. In CLH, T cells usually outnumbered B cells, and a B:T c
ell ratio greater than or equal to 3:1 was not observed in any case. By con
trast, 40% of the MZL cases showed a B:T cell ratio greater than or equal t
o 3:1. No coexpression of CD20 and CD43 was seen in any case of either MZL
or CLH. In summary, the clinical presentations of CLH and MZL are similar.
In contrast to historical criteria for diagnosing cutaneous lymphoid infilt
rates, the presence of reactive follicles favors a diagnosis of cutaneous B
-cell lymphoma (CBCL). In addition, a bottom-heavy or top-heavy growth patt
ern is not a distinctive finding. Marginal zone cells and zones or sheets o
f plasma cells are strong morphologic indicators of marginal zone lymphoma.
The diagnosis of CBCL can be supported in 40% of the cases by demonstratin
g a B:T cell ratio of greater than or equal to 3:1, and confirmed in 70% of
the cases by demonstrating monotypic light chain expression of plasma cell
s on paraffin sections.