Primary Cutaneous Follicle Center Lymphoma ??? ???Crosti Lymphoma???

Abstract

In 1951, Crosti reported on seven patients with 'reticulo-histiocytoma of the back' who presented with figurate erythematous plaques and nodules on the back or lateral trunk. Reticulo-histiocytoma of the back was later classified as a primary cutaneous follicle center lymphoma (PCFCL). A definitive diagnosis of the condition is frequently delayed because of a relative lack of clinical symptoms and difficulties in interpretation of the histologic findings. Indeed, a number of primary cutaneous B-cell lymphomas have been mislabeled as pseudolymphomas in the past. We present a case of PCFCL that initially demonstrated predominantly small T lymphocytes on histology. These findings were interpreted as an inflammatory pseudolymphomatous reaction. However, small lymphocytes, whether B or T cells, in early lesions of cutaneous B-cell lymphomas should not automatically be considered 'reactive.' Persistent antigenic stimulation of lymphocytes in a neoplastic process or by an antigen, for example, Borrelia burgdorferi, can lead to transformation and cell division with development of large blast cells. In our patient, the initial scarcity of B lymphocytes also led to further diagnostic difficulties. Although the association of primary cutaneous B-cell lymphoma with Borrelia infection is known, there are still difficulties in differentiating the condition from pseudolymphoma. Such difficulties can in part be ascribed to the morphologic changes such lymphomas can undergo over time. The initially small number of B cells that may be seen at first in PCFCL infiltrates may increase in number in longer-standing lesions. It is also important to recognize that inability to verify monoclonality should not exclude the diagnosis of lymphoma.

Primary cutaneous lymphoma: two-decade comparison in a population of 263 cases from a Swiss tertiary referral centre

“…As discussed by Kazakov et al and several other authors, the diagnosis of PCMZL can be challenging and can erroneously include cases with pseudolymphomatous reactions. [13][14][15][16] This may mean that several patients were diagnosed with pseudolymphoma, especially between 1990 and 1999, and were therefore not seen as lymphomas in our department. Concerning the pattern of CBCL subtypes, international data are discordant.…”

Eponyms in the literature of cutaneous lymphomas

“…Crosti lymphoma [3,4] In 1951, Crosti reported on seven patients with ‚reticulo-histiocytoma of the back' who presented with figurate erythematous plaques and nodules on the back or lateral trunk. Reticulohistiocytoma of the back was later classified as a primary cutaneous follicle center lymphoma (PCFCL).…”

Transformation of a Cutaneous Follicle Center Lymphoma to a Diffuse Large B-Cell Lymphoma—An Unusual Presentation

“…It shows a predilection for the scalp, forehead, and trunk and dissemination to extracutaneous sites rarely occurs [2]. Transformation of systemic follicular lymphoma (FL) into aggressive non-Hodgkin , s Lymphoma is associated with poor prognosis and has been reported with a wide range of frequency (range between 10%–70%).…”