Interesting (MSK) Cases Meeting 02.05.2019

Dr Ajay Varghese MRCP FRCR Visiting Radiologist Prince of Wales Hospital Case 1 - 25 year old female patient with foot and ankle pain

Case 2 - 73 year old female - Hx of Left rotator cuff tear. Bilateral shoulder pain, ROM severely limited and weakness

Milwaukee shoulder

Destructive shoulder arthropathy due to deposition of Hydroxyapatite crystals

Older women, often with a history of trauma to the region. Symptoms are usually comparatively mild, despite rapid and marked progression of radiographic features.

Radiograph Resembles charcot arthropathy Advanced articular surface destruction with intra articular fragments Subchondral sclerosis Soft tissue swelling Rotator cuff disruption. Superior subluxation of the humeral head in relation to the glenoid fossa . Case 3 - 19 year old male patient with ankle pain

Intraosseous lipoma

•stage 1: sharply delineated, viable lipomas with homogeneous fat content •stage 2: predominantly fatty lesions with central necrosis, calcifications or ossifications •stage 3: heterogeneous, fat-containing lesions with multiple necrosis, cystic transformations, wall sclerosis and extensive calcifications or ossifications. Case 4 - 58 year old female with thigh mass x 1.5 months; 6cm in diameter , non-tender, not compressible, not pulsatile

MRI CONCLUSION: An intramuscular mass in right tensor fasciae lata, with nonspecific MR features. Intramuscular myxoma may be one of the possibilities.

Histopathology DIAGNOSIS Right thigh soft tissue tumor, biopsy:- Myxoid lesion, benign, favor intramuscular myxoma. Intramuscular myxoma Females (~57%) patients between 40-70 years

Clinical presentation The typical presentation is that of a slowly enlarging mass(es) with no malignant potential

Association - Mazabraud syndrome, McCune Albright syndrome

Location – thigh and pelvis

Ultrasound Demonstration of a well-defined hypoechoic to near anechoic mass to the surrounding soft tissue and often shows a heterogeneous echotexture . Posterior acoustic enhancement may be observed in a significant proportion of cases. There may be some internal echoes and increased through transmission . In ~85% of cases, there is a sonographic bright rim sign of increased echogenicity around the myxoma Frequently noted is the bright cap sign seen as a triangular hyperechoic area adjacent to at least one of the poles of the mass . The lesion is hypovascular or avascular on color Doppler US.

MRI •intra-tumoral cysts may be present in a small proportion of cases •pseudocapsule, perilesional/rim of fat and perilesional edema may be present

•T1: hypointense to muscle •T2: hyperintense •T1 C+: different patterns have been described •peripheral enhancement •peripheral and patchy internal enhancement •peripheral and linear internal enhancement •Avid enhancement Case 5 – 75 year old female patient, Right posteromedial deep mass in thigh increasing in size in recent few months, now ~5 cm in size.

MRI Report:Large intermuscular soft tissue tumour, probably a myxoid liposarcoma.

Histopathology: Morphologically, the lesion is compatible with a benign or low grade lesion. Spindle cell lipomatous lesions have to be excluded. Myxoid liposarcoma or Well-differentiated liposarcoma are not supported by the molecular findings. Lipomatous lesions

Benign •lipoma •chondroid lipoma •spindle cell lipoma •pleomorphic lipoma •lipomatosis •lipomatosis of nerve •lipoblastoma or lipoblastomatosis •angiolipoma •myolipoma of soft tissue •hibernoma •lipoma arborescens •thymolipoma •angiomyolipoma •adrenal myelolipoma

Malignant •liposarcoma •thymoliposarcoma Spindle cell lipoma Spindle cell lipoma is a benign lesion in which mature fat is replaced by collagen-forming spindle cells .

Epidemiology Middle aged to elderly men between the ages of 45 and 65 years .

Clinical presentation Spindle cell lipoma has a significant tendency to occur in the subcutaneous tissue of the posterior neck, shoulder, and back .

Radiographic features The diagnosis of spindle cell lipoma should be suggested when a middle-aged man presents with a well-defined complex fatty mass in the subcutis in the posterior neck .

MRI Non-adipose components of SCLs were isointense to skeletal muscle on T1-weighted imaging (T1W) and of variable signal compared to fat on T2-weighted (T2W) sequences . Intense enhancement of the non-adipose component further supports this diagnosis .

Treatment Spindle cell lipoma is a benign lesion that is cured by local excision. It has never been reported to metastasize .

Differential Diagnosis Liposarcoma, schwannoma and neurofibroma Case 6 - 66 years old lady with osteoporosis in 2001. Also found to have hypophosphatemia recently suspicious of oncogenic osteomalacia. Past health: non smoker, non drinker, hypertension, fracture bilateral hip & legs with metallic implants in 2003/ 2015. No other malignancy or TB history. Referred for PET CT Oncogenic osteomalacia, or tumor-induced osteomalacia (TIO) - acquired paraneoplastic syndrome.

Tumours that lead to this condition are classified histologically as Phosphaturic mesenchymal tumors

Tumors, which lead to oncogenic osteomalacia, secrete fibroblast growth factor 23 (FGF-23) - results in decreased phosphate reabsorption in the nephron, causing hypophosphatemia, phosphaturia and low or normal serum 1,25-dihydroxy vitamin D levels

Clinical Presentation: fractures of the long bones, ribs, and vertebrae . Other symptoms include severe bone pain and muscle weakness .

Radiographs show the findings of osteomalacia, such as Looser zones and insufficiency fractures .

Magnetic resonance (MR) imaging and positron emission tomography have been used in localization. The MR findings are nonspecific and not pathognomic for TIO.

Treatment - Tumor resection is the preferred treatment option, as it often results in full recovery from osteomalacia

The differential diagnosis of TIO includes other renal phosphate wasting diseases, such as X-linked hypophosphatemic rickets, autosomal dominant hypophosphatemic rickets, hereditary hypophosphatemic rickets with hypercalciuria, and Fanconi syndrome Gallium-68 DOTATATE PET CT imaging will be better modality for workup of oncogenic osteomalacia.

DIAGNOSIS Distal left posterior thigh soft tissue tumor: -Spindle cell neoplasm, suggestive of Phosphaturic Mesenchymal tumour. Case 7 - 40 year old female patient - SLE with extensive infective tenosynovitis (mycobacterium haemophilum) over both hands and wrists (extensor and flexor). Synovectomy done recently. increased finger swelling post-op. Referred for ultrasound Tenosynovitis - inflammation of the synovial membrane surrounding a tendon and may be seen with or without tendinosis.

The synovial membrane is not usually identified unless there is a pathological swelling.

-increased fluid content within tendon sheath, -thickening of the synovial sheath with or without increased vascularity which can extend into the tendon sheath -peritendinous subcutaneous edema. -peritendinous subcutaneous hyperemia on Doppler imaging.

Mycobacterium marinum (fish tank finger) and Mycobacterium kansasii - most frequent causes of NTM tenosynovitis . Less frequently, M. avium complex, M. szulgai, M. terrae, M. fortuitum, M. chelonae, M. abscessus, M. malmoense and M. xenopi Mycobacterium haemophilum - causes skin, joint, bone, and pulmonary infections in immunocompromised persons and lymphadenitis in children. M haemophilum isolated from Hodgkins patients, AIDS patients, transplant recipients, patients receiving TNF alpha - has been associated with permanent eyebrow makeup and tattoos, as well as accupuncture

M haemophilum is a fastidious (requires special growth media) mycobacterium that requires heme-supplemented culture media and low temperatures for growth. Because of these features, it is probably underdiagnosed. Effective drug combinations include the following: •Rifampin and ciprofloxacin •Ciprofloxacin, clarithromycin, and rifampin •Rifampin and minocycline •Clarithromycin, minocycline, and rifampin Thank You