A case of cutaneous B-cell lymphoma with a storiform stromal reaction

Spindle-cell B-cell lymphoma presenting in the skin

Lymphomas with predominant spindle-cell morphology have only been previously reported in small numbers; such lesions are potentially mistaken for sarcoma or other spindle-cell tumours. We describe a 73-year-old woman who presented with a tumour on the scalp of a few months' duration. Biopsy showed a B-cell lymphoma of follicle centre cell origin with a sarcomatoid appearance and a CD20+, CD10+, CD21+, bcl-6+ immunophenotype. This case highlights the very rare occurrence of spindle-cell B-cell lymphoma presenting in the skin. An awareness of this phenomenon is essential to avoid confusion with a variety of other cutaneous spindle-cell neoplasms and to enable a correct diagnosis to be made, thereby ensuring that appropriate treatment is initiated.

Fibromucinous T-cell lymphoma: a new clinicopathologic variant of mycosis fungoides?

We report a case of mycosis fungoides associated with extensive dermal fibrosis and mucin deposition. The patient developed indurated plaques with diffuse tightening of the skin reminiscent of the sclerosing disorder scleromyxedema, which was later associated with nodules and lymphadenopathy. Skin biopsies showed diffusely thickened collagen bundles in the dermis and mucin deposition with a dense infiltrate of atypical lymphocytes with an immunophenotypic pattern indicative of mycosis fungoides. In our opinion, these clinical and histopathologic features are unusual for mycosis fungoides and can be construed as a distinct fibromucinous variant. Alternatively, this may represent a fibrosing reaction pattern similar to that described with systemic T- and B-cell lymphomas or a variety of inflammatory disorders.

Cutaneous spindle-cell B-cell lymphoma: a morphologic variant of cutaneous large B-cell lymphoma

The morphologic spectrum of large B-cell lymphoma is broad. Several unusual variants have been described such as lymphoma with myxoid stroma, sclerosing B-cell lymphoma, signet ring-cell lymphoma, and multilobated B-cell lymphoma among others. We report on five cases of cutaneous large B-cell lymphoma in which the neoplastic cells were spindle-shaped. In two cases, the clinical features fulfilled those of a primary cutaneous lymphoma; in the three other cases, the lymphoma most likely arose primarily in the skin, but incomplete clinical workups precluded definite categorization. The patients ranged in age from 30 to 89 years and presented with solitary lesions on the trunk or head. Histopathologic examination revealed nodular or dense diffuse infiltrates involving the entire dermis as well as the subcutaneous fat in some cases. Thickened collagen bundles between the spindled cells were present in one case. Cytomorphologic analysis showed the presence of round or oval medium-sized and large-sized lymphocytes with features of centrocytes and centroblasts in some foci, with others dominated by cells with spindle-shaped, elongated, twisted nuclei with dispersed chromatin and scant cytoplasm. Immunohistologic analysis revealed that both round or oval and spindled cells were positive for CD20 in all cases; in all cases tested, these cells were also positive for MIB-1 and were negative for CD3, CD5, CD43, CD45RO, CD21, CD30, CD68, S-100, HMB-45, actin, smooth-muscle actin, and cytokeratin. Bcl-2 was expressed in one of three cases tested. Analysis of the rearrangement of the J(H) gene by polymerase chain reaction performed in one case showed a monoclonal pattern. Spindle-cell large B-cell lymphoma represents a distinctive rare subtype of the cutaneous large B-cell lymphoma and can arise primarily in the skin in some cases. Recognition of this variant is necessary to avoid misdiagnosis of other cutaneous malignant spindle-cell tumors.