Dermatologie

Cas 0710240

Liens et agrandissements sur : images et texte en bleu. Links - Zoom: pictures and highlighted text.
 

Lésion nodulaire du cuir chevelu de 1 cm d'apparition récente, chez un homme de 65 ans, asymptomatique, suivi pour adenocarcinome prostatique traité.

Resection chirurgicale.

 

Recent nodular lesion on the scalp,mesuring 1 cm, in an asymptomatic 65 yo male.He is followed up for treated prostatic adenocarcinoma.

Surgical resection.

 
     
     
     
     
     
     
     
  Coloration des fibres de réticuline   Reticulin fiber stain  
     
  CD20   CD20  
     
  CD3   CD3  
     
  bcl-2   bcl-2  
     
  MIB-1   MIB-1  
 

Diagnostic proposé

 

 

 

 

 

 

 

Lymphome folliculaire de bas grade.

La positivité de la bcl-2 soulève l'hypothèse d'une atteinte cutanée secondaire d'un lymphome folliculaire ganglionaire.

Un bilan par imagerie révèle une polyadénopathie...

 

Proposed diagnosis

 

 

 

 

 

 

 

Follicular lymphoma, low grade

Positivity to bcl-2 raise suspicion of a systemic lymphoma involving the skin secondarily.

Follow up disclosed multiple internal enlarged lymph nodes by scan imaging.

 
 

Arguments

Dans le texte de la réference ci-dessous:

 

 

In the highlighted text of the reference below:

 

BLOOD, 15 MAY 2005 VOLUME 105, NUMBER 10

Primary cutaneous follicle-center lymphoma

Definition.

Primary cutaneous follicle center lymphoma (PCFCL) is defined as a tumor of neoplastic follicle center cells, usually a mixture of centrocytes (small and large cleaved follicle center
cells) and variable numbers of centroblasts (large noncleaved follicle center cells with prominent nucleoli), with a follicular, a follicular and diffuse, or a diffuse growth pattern, which generally
present on the head or trunk. Lymphomas with a diffuse growth pattern and a monotonous proliferation of centroblasts and immunoblasts are, irrespective of site, excluded and are classified as PCLBCL.

Clinical features

PCFCL has a characteristic clinical presentation with solitary or grouped plaques and tumors, preferentially located on the scalp or forehead or on the trunk, and rarely on the legs. Particularly on the trunk, these tumors may be surrounded by erythematous papules and slightly indurated
plaques, which may precede the development of tumorous lesions for months or even many years. In the past, PCFCLs with such a typical presentation on the back were referred to as “reticulohistiocytoma of the dorsum” or “Crosti lymphoma" Presentation with multifocal skin lesions is observed in a small minority of patients, but is not associated with a more unfavorable prognosis. If left untreated, the skin lesions gradually increase in size over years, but dissemination to extracutaneous sites is uncommon.

Histopathology.

PCFCLs show nodular to diffuse infiltrates with almost constant sparing of the epidermis. The histologic picture is variable, which relates primarily to the age and the growth rate of the biopsied skin lesion as well as the location. Clear-cut follicular growth pattern is more commonly observed in lesions arising on the scalp than those presenting on the trunk. Small and early lesions contain a mixture of centrocytes, relatively few centroblasts, and many reactive T cells. Large centrocytes, often multilobated, are a common feature of PCFCL. The large neoplastic B cells may have a fibroblast-like appearance. In small and/or early lesions a clear-cut follicular growth pattern or, more often, remnants of a follicular growth pattern may be observed. If present, the abnormal follicles are composed of malignant bcl-6 follicle center cells enmeshed in a network of CD21 or CD35 follicular dendritic cells. The follicles are ill-defined, lack tingible body macrophages, and generally have a reduced or absent mantle zone.With progression to tumorous lesions the neoplastic B cells increase both in number and size, whereas the number of reactive T cells steadily decreases. Follicular structures, if present before, are no longer visible except for occasional scattered CD21 or CD35 follicular dendritic cells. Tumorous skin lesions generally show a monotonous population of large follicle center cells, generally large centrocytes and multilobated cells, and in rare cases spindle-shaped cells, with a variable admixture of centroblasts and immunoblasts. Usually, a prominent stromal component is present.


Immunophenotype.

The neoplastic cells express the B-cell–associated antigens CD20 and CD79a, and may show monotypic staining for surface immunoglobulins (sIgs). However, absence of detectable sIg is common in tumorous lesions showing a diffuse population of large follicle center cells. PCFCLs consistently express bcl-6. CD10 expression is particularly observed in cases with a follicular growth pattern, but is uncommon in PCFCLs with a diffuse growth pattern. Staining for CD5 and CD43 is negative. Unlike nodal and secondary cutaneous follicular lymphomas, PCFCLs do not express bcl-2 protein or show faint bcl-2 staining in a minority of neoplastic B-cells. Staining for MUM-1/IRF4 is negative.


Genetic features.

Clonally rearranged immunoglobulin genes are present. Somatic hypermutation of variable heavy and light chain genes has been demonstrated, which further supports the follicle center cell origin of these lymphomas. In most studies PCFCLs, including cases with a follicular growth pattern, do notshow the t(14;18), which is characteristically found in systemic follicular lymphomas and a proportion of systemic diffuse large B-cell lymphoma.(see “Comment” under “Primary cutaneous follicle-center lymphoma”). Inactivation of p15 and p16 tumor suppressor genes by promotor hypermethylation has been reported in about 10% and 30% of PCFCLs, respectively. Chromosomal imbalances have been identified by comparative genomic hybridization (CGH) analysis in a minority of PCFCLs, but a consistent pattern has not yet emerged.In a recent study using interphase fluorescence in situ hybridization, no evidence for translocations involving IgH, myc, or bcl-6 loci were found.45 PCFCLs have the gene expression profile of germinal center–like large B-cell lymphomas.


Prognosis and predictive factors.

Regardless of the growth pattern (follicular or diffuse), the number of blast cells, or the
presence of either localized or multifocal skin disease, these PCFCLs have an excellent prognosis with a 5-year survival of more than 95%. A recent study suggests that strong expression of bcl-2 in PCFCLs with a diffuse large-cell histology is associated with a more unfavorable prognosis.

Therapy

In patients with localized or few scattered skin lesions, radiotherapy is the preferred mode of treatment, even in cases with a predominance of large “cleaved” cells. Cutaneous relapses, observed in approximately 20% of patients, do not indicate progressive disease and can be treated with radiotherapy as well. Anthracycline-based chemotherapy is required only in patients with very extensive cutaneous disease and patients developing extracutaneous disease. Recent studies report beneficial effects of systemic or intralesional administration of anti-CD20 antibody (rituximab) therapy in small series of PCFCLs, but the long-term effects of this approach have yet to be determined.

Comment

Characteristically, PCFCLs do not express bcl-2 protein, or show faint bcl-2 staining in a minority of tumor cells, and do not show the t(14;18).However, recent studies report the presence of t(14;18) and/or bcl-2 expression in a significant minority of PCFCLs.43,153,165-167 Whether these discrepant results are the result of differences in patient selection (eg, incomplete staging) or different definitions for bcl-2 positivity, or represent regional differences is as yet unknown. Importantly, in PCFCLs with a follicular growth pattern there are no differences in clinical presentation and behavior between bcl-2 and/or t(14;18)-positive and -negative cases.In contrast, recent studies suggest that expression of bcl-2 protein by more than 50% of the neoplastic B cells in PCFCLs with a diffuse proliferation of large centrocytes, observed in approximately 15% of cases, is associated with a more unfavorable prognosis.158 Further studies are warranted to define the clinical and biological significance of bcl-2 expression and/or the presence of t(14;18) observed in some cases of PCFCL. Notwithstanding, demonstration of bcl-2 expression and/or t(14; 18) should always raise suspicion of a systemic lymphoma involving the skin secondarily.

For more details on cutaneous lymphomas, see (click) the review article below

BLOOD, 15 MAY 2005 VOLUME 105, NUMBER 10