Orbital Involvement by Primary Cutaneous Diffuse Large B-Cell Lymphoma-Leg Type.

An 84-year-old female patient presented with an impressive, large lesion on the medial canthus of the OS. The lesion, which was initially treated as dacryocystitis, was reddish and crusty obstructing the visual axis (Fig. 1A). Orbital CT disclosed an infiltrating mass in the inferomedial aspect of the left orbit, maxillary, and ethmoid sinuses (Fig. 1B). A positron emission tomography scan showed abnormal metabolic activity only in the lesion (Fig. 1C). Although the presumptive diagnosis was an aggressive carcinoma, a skin biopsy showed that the mass was a primary cutaneous diffuse large B-cell lymphoma-leg type, classifying the tumor as T4cN0M0, according to the 8th edition of the American Joint Commission on Cancer. This peculiar nongerminal center origin tumor is defined by a diffuse proliferation of large lymphoid cells with centroblastic morphology (Fig. 1D, hematoxylin and eosin, ×400), with a typical immunohistochemistry pattern consisting of positivity for CD 20 + (Fig. 1E) and strong expression of both bcl-2 (Fig. 1F) and MUM-1 (Fig. 1G). CD 10 was negative. Despite its high mitotic index (Ki-67 = 90%), the tumor evolved with complete remission (Fig. 2) after 6 cycles of bendamustine HCl and rituximab. Six months post-therapy, there was no evidence of recurrence. Primary cutaneous diffuse large B-cell lymphoma-leg type typically affects one or both lower legs of elderly individuals. The periorbital region is an extremely uncommon location of the disease with just 1 case reported in the literature. To our best knowledge, it has never been found invading the orbit. Treatment includes radiotherapy and polychemotherapy. The estimated 5-year cause-specific survival rate is approximately 50%, and the prognosis worsens when the lymphoma is on the legs.FIG. 1FIG. 2