Anaplastic large-cell lymphoma primarily infiltrating femoral muscles

Abstract

Dear Sir, Primary extranodal lymphoma is known to occur in the gastrointestinal tract (so-called MALToma), orbit, skin, bone, and central nervous system. Among 7,000 cases of malignant lymphomas diagnosed at the Mayo Clinic between 1976 and 1986, only eight cases initially presented as soft tissue masses in the extremities [1]. Especially, primary muscular lymphoma is relatively rare, accounting for less than 1% of extranodal lymphoma [2]. Skeletal muscle can be involved in non-Hodgkin’s lymphoma as a part of disseminated disease, as a local extension from lymphomatous deposits in the adjacent lymph nodes or bones, or as a primary site of disease. Although anaplastic large cell lymphoma (ALCL), so-called Ki-1 lymphoma, frequently exhibits extranodal disease, primary muscular involvement is extremely rare. Recently, the anaplastic lymphoma kinase (ALK) protein was shown to identify a subgroup of nodal ALCL with an excellent prognosis. On the contrary, absence of ALK expression in tumor usually denotes resistance to treatment and unfavorable prognosis. A 21-year-old Asian male presented with a 2-month history of progressively painless swelling of the right thigh. There were no constitutional symptoms such as fever, weight loss, local heat, or skin erythema. Pertinent physical examination included significance for diffuse swelling of right thigh extending to right knee joint without significant skin change or adjacent lymphadenopathy. Computed tomography (CT) scan demonstrated swelling and edematous change of adductor muscular groups, including biceps femoris, gluteus intermedius muscle, and surrounding subcutaneous tissue. A venography of right lower extremity carried out in a regional hospital found a questionable filling defect at the right popliteo-femoral vein prompt to the diagnosis of deep venous thrombosis. However, the muscular swelling did not respond to subsequent anticoagulant therapy. He was then referred to our center, and a magnetic resonance imaging (MRI) scan demonstrated diffuse nodular masses infiltrating the posterior and medial compartments of the right thigh and vastus intermedialis muscle (Fig. 1a,b). Those masses were marked hyperintense on T2-weighted images (Fig. 1c) with enhancement after the gadolinium administration. Incisional biopsy of biceps femoris and histological examination disclosed diffuse infiltration of large pleomorphic cells with hyperchromatic nucleus and prominent nucleoli (Fig. 2a,b). Upon immunohistological staining, these atypical cells were positive for CD45 and CD30 (Ki1) and negative for CD3, CD5, CD15, CD19, CD20, CD56, and nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) protein (also named P80) (Fig. 2c). Further systemic staging work-up did not find any nodal and bone marrow involvement. Intensive chemotherapy, using cyclophosphamide, doxorubicin, vincristine, prednisolone, and etoposide (CHOP-E) was conducted, but his disease started to progress after completion of third cycle treatment. Subsequent salvage therapy including high-dose methotrexate followed by weekly vinblastine and external beam radiotherapy can only achieve stable disease. Nine months after diagnosis, progressive dyspnea developed, and the chest X-ray disclosed right massive pleural effusion containing CD30+ lymphoma cells. After obtaining a partial response to salvage regimen with mesna, ifosphamide, mitoxantrone, etoposide (MINE) and etoposide, methylprednisolone, cytarabine, cisplatin (ESHAP), he subsequently underwent high-dose chemotherapy (busulfan and cyclophosphamide) followed by autologous peripheral blood stem cell transplantation. Despite experiencing a brief period of stable disease, he finally succumbed to rapid systemic dissemination 2 months after PBSCT. W.-P. Liao . M.-S. Dai . N.-S. Yao (*) Division of Hematology/Oncology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan e-mail: nancynsy@yahoo.com.tw Tel.: +886-2-87927208 Fax: +886-2-87927209