Procesos linfoides B cutáneos con patrón nodular / Cutaneous B cell processes with nodular pattern

Cutaneous lymphomas are low grade malignant neoplasms with favourable prognosis. Those related to the germinal centre with nodular pattern may be: follicular lymphomas (LFC) or extranodal marginal zone B-cell lymphomas (LMC). They are difficult to tell apart, and from reactive processes like cutaneous follicular hyperplasia and cutis immunocytomas. The objective of this study was to check the incidence and the value of both histology and immunohistochemistry in differential diagnosis. Fifty six patients with cutaneous lymphomas were selected within the period 1995-2004. The biopsies were studied with hematoxilin eosin and immunohistochemistry. Thirty two out of the fifty six cutaneous lymphoid infiltrates were of T origin (57.1%) and twenty four of B origin (42.8%), ten out of this last figure (17.7%) were lymphoid processes with nodular pattern Four LFC, three LMC and three HLC were diagnosed. Convergent follicles with scarce mantle and germinal centres with monomorph celullarity were observed in the LFC. Among the LMC, follicles with prominent mantle and nests of monocitoid cells in the mantle, interfollicular zone and in the germinal centers observed. In the HLC macrophages with detritus were found in the germinal centers. LFC showed: CD20 (+), CD 10 (+), bcl-2 (+) or (-), and bcl-6 (+) in the follicle and in the interfollicular area. LMC showed: CD 20 (+), bcl-2 (-), CD 10 (+/-), and bcl-6 (+) in the follicle, and bcl-2 (+), CD10 (-/+) and bcl-6 (-) in the interfollicular area. The HLC results were: bcl-2 (-), bcl-6 (+) and CD 10 (-) in the follicle and bcl-2 (+), bcl-6 (-) and CD 10 (-) in the interfollicular zone. We conclude that lymphoid B cell processes with nodular pattern are unusual. Histology and immunohistochemistry proved to be useful in the differential diagnosis of these lymphomas, and for differentiating these from lymphoid hyperplasias or non tumoral hyperplasias.

Expressions of p53 and p21 in Primary Gastric Lymphomas

The p21 overexpression is thought to be a consequence of the p53 induced activation of the p21 gene. The immunohistochemical evaluation of p53 and p21 can be a valuable means of assessing the functional status of the p53 gene product. We examined the overexpression of p21 and p53 proteins in primary gastric lymphomas and the correlation with prognosis. A total of 32 cases of gastric lymphomas was classified into low-grade lymphomas of mucosa-associated lymphoid tissue type (n=16) and high-grade B-cell lymphomas (n=16). In low-grade lymphomas, only one case showed p53 positivity and all cases were p21-negative. In high-grade lymphomas, seven cases were p53+/p21- (44%), one case was p53+/p21+ (6%), and eight cases were p53-/p21- (50%). The p53+/p21- cases had a much lower percentage of patients sustaining a continuous complete remission state (3/7, 43%) compared with other cases (6/7, 86%). From these results, we concluded that p21 expression is rare in primary gastric lymphomas. Therefore, p53-positive lymphomas can be assumed as having p53 mutation. And combined studies of p53 and p21 may be used as a prognostic indicator in primary gastric high-grade lymphomas.

T cell rich B cell lymphoma (TCRBCL): study of sixteen cases with review of literature.

T cell rich B cell lymphoma (TCRBCL) is a recently described variant of diffuse non Hodgkin's lymphoma (NHL), the acronym of which has gained wide acceptance among hematopathologists in a relatively shorter period of time. The recognition of this entity requires immunohistochemical facilities especially on paraffin embedded tissues. TCRBCL is one of the many examples in the diagnostic anatomic pathology which emphasizes the need of immunocytochemistry and availability of this technique at least in referral laboratories. One of the differential diagnosis in this case includes lymphocyte predominance Hodgkin's disease (LPHD) which is the most favorable prognostic histologic subtype of Hodgkin's disease (HD) while TCRBCL is an aggressive B Cell NHL and should be treated as high grade large cell lymphoma. The other close differential includes peripheral T cell non-Hodgkin's lymphoma (PTCL). We reported sixteen (16) cases of TcRBCL diagnosed during a period of two and a half years (January 1995 to June 1997). HD and PTCL were the main differential diagnoses in most of these cases. The median age at diagnosis was 39 years and male to female ratio was equal. TCRBCL was nodal in location in 15 cases and a single case in extranodal site presenting as spinal tumor. The mean neoplastic B cell population was 12%, while that of reactive T cells was 82%. A significant polymorphous inflammatory cellular background was noted in 5 cases. Reed-Stenberg like cells were observed in 3 cases. Immunoglobulin light chain restriction studies were performed in fourteen cases and revealed lambda light chains in ten cases while in four cases kappa light chains were present.