GCT of tendon sheath

 

GCT of tendon sheath

Synonyms: 

Giant cell tumour of the tendon sheath 

Tenosynovial giant cell tumour

Pigmented villonodular tumour of the tendon sheath (PVNTS)

Localised or focal nodular synovitis.

They are usually seen as localized, single, slow-growing, subcutaneous soft tissue nodules, with or without pain on local examination, very common in hand and wrist, encountered during 3rd to 5th decades with slight female predilection.

On MRI, well defined ovoid lesion with low signal on T1 and T2 images, mild to moderate enhancement on post contrast, may show pressure erosion of adjacent bone, or rarely can invade the bone mimicking an intraosseous lesion on imaging.

Actually they thought to arise from the tendon sheath but unclear whether they represent neoplasms or just reactive masses. Intra articular GCT involving larger joints also very common as in this case. 

Histolopathogically identical to pigmented villonodular synovitis (PVNS), composed of fibroblasts and multinucleated giant cells, foamy histiocytes, and inflammatory cells on a background fibrous matrix.

Being benign local surgical excision usually suffices with local recurrence of nearly in 10-20% of cases requiring more extensive surgery with or without radiotherapy.

Talocalcaneal ganglion cyst

A subtalar ganglion with intraosseous component in the calcaneus.

Ganglion cysts are very common mucin-containing cystic lesions that affect a wide variety of joints of the body, including foot and ankle.

COVID 19 Cerebritis

Clinically: A known case of COVID 19 positive admitted for fever and breathlessness.

After five days of hospital admission developed sinusitis, headache and started worsening repidly. Subjected for MRI due to sudden onset loss of consciousness and neurological examination revealed new onset ophthalmoplegia. 

MRI shows bilateral geographic shaped patchy T2 hyperintensities involving frontal lobes with diffusion restriction at the floor of anterior cranial fossa. Mild lepto meningeal enhancement on post contrast. 

An associated marked bilateral paranasal sinusitis.

Possibility of COVID 19 Cerebritis, Neuro invasiveness by transnasal route suggested and can be attributed to known Neurotropism of the virus. 

Neurotropism of Covid 19

Neuronal pathway is one of important way of spread of neuropathic viruses like Cov to enter central nervous system. These viruses can migrate with the help of sensory as well as motor nerve endings and have ability of retrograde as well as antegrade spread along the olfactory nervous system due to the unique anatomical organisation of olfactory nerves and olfactory bulb in the nasal cavity and fore brain. As a result, Cov after paranasal sinus infection can enter brain through olfactory tract in early stages of infection rapidly, within seven days of infection as in our case.

Madhura mycosis of foot

 

Sagittal T2w

Sagittal T1w

Sagittal STIR

MRI study of ankle/foot with x-ray correlation shows:

A lobulated abnormal soft tissue measuring approximately 70 mm in length and 40 mm in depth on dorsal aspect of foot encasing extensor tendons with hypo intense signal on T2-weighted images, “dot in a circle” sign on MRI. 

Soft tissue density on x-ray without dystrophic calcification on x-ray. Lytic destruction of adjacent anterior corner of tibia on MRI and x-ray. Associated tibio talar joint effusion. Multifocal ovoid lytic lesion with sclerotic rim on x-ray involving distal end of tibia with fluid signal on MRI. Marginal lytic destruction of distal end of fibula. Circumferential punched-out marginal erosion of neck of talus which is markedly thinned out with an associated marrow oedema on STIR. Multifocal marrow oedema involving tarsal bones, tenosynovitis of extensor as well as plantar tendons.

Multiple ulcers, nodules and discharging sinuses on skin of dorsal aspect of foot when examined clinically.

Imaging diagnosis: Madhura mycosis of foot with osteomyelitis of tibia.