Clinical Profile:

A 60 year old lady came to orthopedic OPD with complaints of pain over the right shoulder joint since one month. There was no history of trauma. The symptoms had gradually progressed with time to the extent that she felt excruciating pain on any movement associated with right shoulder joint.

There was swelling and tenderness over right shoulder joint. The range of movements was restricted and painful. There was no distal neurovascular deficit.

Radiological Investigations:

Radiograph of the right shoulder joint shows an ill defined fluffy slerotic lesion involving superior and lateral border of the glenoid, scapular body immediately adjacent and the coracoid process, The lesion had a wide zone of transition. There right costophrenic angle is obliterated.

Axial and coronal sections of the plain and contrast enhanced CT of the right shoulder show a predominantly sclerotic lesion involving the lateral border , body, spine , coracoid process , glenoid fossa of the scapula with solid periosteal reaction. Adjoining soft tissue swelling is seen in the right subscapularis and supraspinatus muscles.

MRI of the right shoulder with scapular region was performed using T1 and T2 weighted images in multiple planes. Post contrast fat saturated T1 images were also acquired.

MRI shows a lobulated heterogeneous lesion in the body , glenoid , spine , coracoid and acromion processes of scapula. The lesion is hypointense on T1 weighted images and heterogeneous on STIR images. There is mild heterogeneous post contrast enhancement.

The lesion also involves supraspinatus, infraspinatus , teres minor and subscapularis muscles.

Radiological diagnosis:

On the basis of the above image findings a provisional diagnosis of osteosarcoma of the scapula was made. However considering the age of the patient metastasis was a differential diagnosis.

A diagnostic biopsy was performed and specimen was sent for histopathology and immunohistochemistry

Histopathology was suggestive of metastasis from adenocarcinoma of unknown origin

Discussion:

The differential diagnosis of these radiological images include:

•Chondrosarcoma :

•25% of all primary malignant bone tumors

•There is presence of ring and arc calcification¹

•Lytic pattern , deep endosteal scalloping and soft tissue extension is common.

•4^th to 5^th decade – male preponderance¹

•Presentation : pain , palpable mass

•Distribution : Long bones (femur , tibia , humerus), pelvis , posterior elements of vertebra , ribs

Imaging findings⁵:

Plain radiographs 4⁴ :

–Lytic lesion

–Intralesional ring and arc or popcorn calcification

–Endosteal scalloping (2/3^rd cortical thickness )

–Moth eaten appearance

–Cortical thickening and periosteal reaction

•CT :

–Heterogeneous contrast enhancement ⁴

MRI :

–Presence of very high intensity in non-mineralized or calcified portions^2,3

–Heterogeneous contrast enhancement ^2,3

^Osteosarcoma

•Malignant bone forming tumors⁴

•2^nd most common primary bone tumor (after multiple myeloma)

•Presentation : Pain , swelling and there may be presence of pathological fracture

•Most common sites of occurrence are around knee joint, fibula , mandible, pelvis and vertebrae⁴

•Typically occurs in young patients (10-20 years) with 75% taking place before the age of 20 because the growth centres of the bone are more active during puberty/adolescence ⁸

•Depending on the dominant process , they are divided into three patterns :

•Lytic metastases

•Sclerotic metastases

•Mixed lytic and sclerotic metastases

•Lytic bone metastases occur from diverse primary tumors and are more common than sclerotic metastasis.

•Common primary tumors of their origin include

–Thyroid carcinoma

–Renal cell carcinoma

–Adrenal gland carcinoma and pheochromocytoma

–Gastrointestinal carcinoma

–Wilms tumor

–Ewing’s Sarcoma

–Melanoma

–Hepato cellular carcinoma

Squamous cell carcinoma of skin

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9.Murphey MD, Robbin MR, Mcrae GA et-al. The many faces of osteosarcoma. Radiographics. 17 (5): 1205-31. Radiographics (abstract) - Pubmed citation

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