Cutaneous B-cell lymphoma. An unusual presentation

Primary Cutaneous B‐Cell Lymphoma

“…The pathologic diagnosis of lymphoma of the skin requires immunohistochemical studies to differentiate cutaneous B‐cell lymphoma from the more common cutaneous T‐cell lymphoma 6 . Because B‐cell lymphomas are the most common form of internal nodal and extianodal lymphoma a thorough search for other foci of disease is essential to stage adequately the patient with cutaneous B‐cell lymphoma 10 .…”

“…The characteristic lesions are smooth, erythematous to violaceous nodules that lack ulceration and are most commonly located on the trunk or the head and neck region 3,5 . Pathologic differentiation of true B‐cell lymphoma from benign (reactive) lymphoid hyperplasia and malignant cutaneous T‐cell lymphoma requires immunoperoxidase techniques and, in some cases, immunoglobulin gene rearrangement studies, in addition to routine microscopy 6 . Histologic subclassification of cutaneous B‐cell lymphoma is not always possible in the absence of lymph node pathology, although a working formulation has been proposed 6,7 …”

A Case of Cutaneous B‐cell Lymphoma with a Storiform Stromal Reaction

“…Lymphocytic infiltration in cutaneous B-cell lymphoma is evident microscopically as a dense monomorphous infiltrate located predominantly in the mid to lower dermis with occasional extension into the subcutaneous fat (20). Immunohistochemically, the infiltrate of pseudolymphoma shows a polyclonal pattern as well as admixed T cells, and the B-cell clusters are always surrounded by distinct T zones (21,22). Medium and large lymphoid cells in biopsy samples from the patient were positive for CD20, CD22 and HlA-DR, and the B-cell clusters were not surrounded by T-cell zones.…”

Pitfalls in the Diagnosis of Cutaneous Lymphoma

“…35 Isolated reports of B-cell lymphomas exhibiting epidermotropism and mimicking MF have been cited in literature. 3,[36][37][38][39][40][41][42][43][44][45] In 8 of these epidermotropic B-cell lymphomas, the neoplastic B cells involved the epidermis as demonstrated by IHC (Table 3), 3,[36][37][38][39][40][41] whereas in 2 of them, the type of epidermotropic cells was not specified. 42,43 In 5 cases, the intraepidermal cells were reactive T cells in an otherwise B-cell lymphoma, giving the false impression of T-cell morphology.…”

“…3,44,45 Regardless of the lineage of intraepidermal lymphocytes, some of these B-cell lymphomas histologically and clinically mimic MF in the form of a pruritic rash as the primary clinical presentation. 3,36,37,45 Amongst the 8 cases, where true B-cell epidermotropism was seen, 4 had systemic involvement and 4 of the 8 were marginal zone lymphomas (MZLs) 3,[36][37][38][39][40][41] (Table 3). Involvement of pilosebaceous unit epithelium and/or epidermis was seen in 4 cases in a series of 15 cases of cutaneous B-cell MZL.…”