Primary cutaneous follicular lymphoma, PCFCCL

Definition

A primary lymphoma of skin showing neoplastic follicles with the cytomorphology and immunophenotype (CD10 or bcl-6 positivity) of follicle centre cells. There should be no extracutaneous lymphoma at the time of diagnosis or for a time thereafter (6 months according to reference 4).

Epidemiology

Patients have a median age of about 60 years, similar to the average for secondary cutaneous follicular lymphoma⁴. Disease before the age of 40 years is rare⁴.

Clinical features

Occur most frequently on the head and neck, as does secondary cutaneous follicular lymphoma². It presents as solitary or grouped papules, plaques or tumours. Some patients have a long history of "pseudolymphoma"⁴.

Histopathology

Neoplastic follicles are seen in the dermis in at least part of the infiltrate. The lymphoid population consists of centrocytes (small and large cleaved follicle centre cells) and a variable number of centroblasts (large non-cleaved follicle centre cells with prominent nucleoli)⁴. There is usually a Grenz zone^1,2 separating the infiltrate from the epidermis, although in some cases epidermotropic T-cells may be present¹. The infiltrate may be "top heavy" or "bottom heavy" and may infiltrate the subcutis to a variable extent⁴. The neoplastic follicles may have mantles that are thick, thin or discontinuous⁴. The mantle cells may infiltrate the follicles to impart a "floret-like" pattern⁴. Rarely, reactive follicles may also be present^1,2. There may be a diffuse neoplastic component, which is usually low grade but may take the form of DLBCL (in the WHO classification, see A study comparing primary and secondary cutaneous large B-cell lymphomas).

Immunohistochemistry

The EORTC defined PCFCCL as CD10-/bcl-2-, not associated with the t(14;18): others do not apply this definition.

	Primary cutaneous follicular lymphoma		Secondary cutaneous follicular lymphoma
CD3		reactive T-cells positive
CD5	0/161
CD10	13/161, 13/152, 27/304		30/314
CD20	16/161, 18/182,
CD21		FDCs positive1,2
CD23	6/161	FDCs positive1,2
CD43	4/16 (all 4 cases weak)1, 6/112
CD79a	18/182
bcl-2	13/16 (weak in 5 cases)1, 9/152 , 0/52, 17/304		31/314
bcl-6	16/161, 15/152, 28/284		28/284

PCR analysis for t(14;18) was negative in all 28 cases examined in three studies(0/14¹, 0/10², 0/4³), positive in 4 of 13 case in a fourth⁴. Positivity occurs in systemic FL with cutaneous involvement (3/4³,10/13⁴).

Differential diagnosis

• Systemic FL with cutaneous involvement; suggested by presence of t(14;18). Thorough staging is required. PCFCCL is more often grade 3, more likely to have a disrupted but thick mantle and more likely to show a floret pattern⁴.

• Primary cutaneous diffuse large B-cell lymphoma: a diffuse infiltrate of centroblasts and immunoblasts.

Prognosis

Compared with nodal follicular lymphoma, there appears to be a higher remission rate , albeit with a high relapse rate in skin or lymph nodes^1,2 and good overall survival. 5-year survival is 89-97%^4,5. A diffuse large cell histology and strong positivity for bcl-2 may be associated with a worse prognosis⁵.

References

¹ Goodlad, J.R., Krajewski, A.S., Batstone, P.J., McKay, P., White, J.M., Benton, E.C., Kavanagh, G.M. and Lucraft, H.H. Primary cutaneous follicular lymphoma: a clinicopathologic and molecular study of 16 cases in support of a distinct entity. Am J Surg Pathol 2002;26:733-41.

² Franco, R., Fernandez-Vazquez, A., Rodriguez-Peralto, J.L., Bellas, C., Lopez-Rios, F., Saez, A., Villuendas, R., Navarrete, M., Fernandez, I., Zarco, C. and Piris, M.A. Cutaneous follicular B-cell lymphoma: description of a series of 18 cases. Am J Surg Pathol 2001;25:875-83.

³ Child, F.J., Russell-Jones, R., Woolford, A.J., Calonje, E., Photiou, A., Orchard, G. and Whittaker, S.J. Absence of the t(14;18) chromosomal translocation in primary cutaneous B-cell lymphoma. Br J Dermatol 2001;144:735-44.

⁴ Kim BK, Surti U, Pandya A, et al. Clinicopathologic, immunophenotypic, and molecular cytogenetic fluorescence in situ hybridization analysis of primary and secondary cutaneous follicular lymphomas. Am J Surg Pathol 2005; 29:69-82

⁵ Campo E, Chott A, Kinney MC, et al. Update on extranodal lymphomas. Conclusions of the Workshop held by the EAHP and the SH in Thessaloniki, Greece. Histopathology 2006; 48:481-504 FULL TEXT

This page last revised 28.4.2006.

©SMUHT/PW Bishop