Presentation of a lymphoma with a painful mass in scapular region

A 56-year-old woman presented to the ED with a several months history of pain in her right shoulder. Physical examination revealed a swelling and palpable mass. There was no significant past medical history.  

An X-ray, MRI and thoracoabdominal CT were performed. X-ray showed enlargement of the soft tissue overlying the right scapular girdle. While MRI demonstrated osseous and soft tissue involvement. Bone findings consisted of marrow infiltration in the body and spine of scapula and in the acromion with extension to the clavicle through acromioclavicular joint. The marrow disease did not associate cortical destruction, excepting the acromion where discrete cortical permeation was presented.  The soft tissue component consisted of multiple masses and diffuse infiltration in rotator cuff and deltoid. These lesions were isointense with muscle on T1, had intermediate signal between muscle and fat on T2, and with homogeneous enhancement after the administration of IV contrast. Through the possibility of malignant tumour, the thoracoabdominal CT was performed, and it showed retro and intraperitoneal masses without other bone and soft tissue lesions. US-guided biopsy in shoulder confirmed the diagnosis of diffuse large B-cell lymphoma (DLBCL)

Lymphoma of the bone accounts for 7% of all bone malignant tumours and 5% of extranodal lymphomas [1] and is more frequent in patients over 30 years. It can be primary bone lymphoma (PBL) or disseminate lymphoma with secondary osseus involvement. The PBL is within a single bone with no evidence of lymphomatous disease elsewhere for at least 6 months after diagnosis [2]. The osseus involvement is usually due to non-Hodgkin and with diffuse large cell (DLBCL), the most common cell type [3].

The clinical presentation includes bone pain, palpable mass, and B-symptoms. While PBL is more common in appendicular skeletal, the secondary bone lymphoma prefers the axial and flat bones such as scapula and ribs. The bone lymphoma may cross to adjacent bone by invading the joint, a specific sign that lymphoma shares with other tumours like metastasis, chordomas and chondrosarcomas, and with the infections [4].

Plain radiographic appearance is variable and non-specific. The permeative lytic pattern is the most common presentation. Sometimes the bone lymphoma shows normal appearance on radiographic and CT, and in these cases, the MRI plays a fundamental role. MRI imaging is more accurate, showing infiltration of the marrow with low signal on T1-weighted imaging and a moderate high signal on T2, except when the lymphoma has a high content of fibrous tissue that shows low signal on T2.  

The pattern of large soft tissue masses without extensive cortical destruction is common. This is a specific feature of small round cells tumours such as multiple myeloma, lymphoma, and Ewing sarcoma [5]. This is explained by the spread of tumour cells from the marrow through small vascular channels that cross the cortex into the surrounding soft tissue.

The final diagnosis was DLBCL stage IV. The patient was treated with chemotherapy: R-DA-EPOCH scheme (rituximab, etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin) and get to disappearance of the shoulder masses on physical examination.

In conclusion, the bone lymphoma has non-specific radiological features but recognition of certain characteristics such as (1) the involvement of adjacent bone crossing the joint, (2) the presence of extensive soft tissue mass with minimal cortical destruction and (3) patients with insidious bone pain that persist for months and sometimes with systemic symptoms, help to do the diagnosis.

Although MRI findings may suggest the diagnosis of bone lymphoma, the biopsy is mandatory. MRI, and particularly Gd-enhanced sequences, can determine the response to therapy, with a direct impact on individual care.

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