Trevor disease MRI

Clinical details, discharge summary mentions corrective osteotomy done for congenital progressive uni lateral knee deformity. Previous imaging details not available.

This MRI of knee joint shows post-operative status with corrective osteotomy for femur and tibia.

Well defined bone signal intensity outgrowth with cortex and medulla involving medial epiphysis of distal end of femur, epiphysis of tibial tuberosity with distinct cortex, medulla and fatty marrow in continuity with parent bone. Marked enlargement of patella with fragmentation.

Trevor’s disease

Synonym: Dysplasia epiphysealis hemimelica.

An extremely rare, approximately 1:1,000,000, congenital, non-hereditary condition consist of multiple osteochondromas arising from the epiphyses. Age of presentation is young children with slight male predilection.

There are three different types of involvement. The classic form has characteristic hemimelic distribution involving more than one bone or epiphysis within a single lower extremity. The localised form encompasses single bone involvement, either unilateral or bilateral. The generalised form incorporates the whole limb from pelvis to foot.

The abnormalities comprising the lower extremity is more common than upper, distal ends are more frequently encountered than upper ends of bone, medial aspects predilection is twice more common than lateral. The most common site of involvement is distal end of femur.

The condition typically demonstrates an irregular bone density mass on x-ray/CT arising from the epiphysis. The bony growth delineates areas of fatty marrow as well as foci sclerosis secondary to ossification on MRI. The illustration of continuity of cortex and medulla with the parent bone is must to end the search.

The bony growth can result in widening of joint space, deformity, bursa formation with soft tissue oedema, bursitis, tendinitis secondary to chronic irritation. The bony overgrowth can land up with fragmentation, detachment forming intra-articular bony loose body and changes of secondary osteoarthritis in advanced case.

Medial patellar plica syndrome

Clinically young patient presented with anteromedial knee pain.

MRI sagittal T2 and axial T2 images delineates a linear well-defined low signal intensity band running across medial patellofemoral recess. However, there is no obvious associated bone marrow oedema involving medial articulating facet of patella or medial femoral trochlea. Mild associated joint effusion.

Medial plica mentioned in the report with joint effusion.

Medial plica syndrome

Synonym: synovial plicae of the knee.

The another common cause of anterior knee pain typically present with pain on anteromedial aspect of the knee, just cranial to the joint line with or without associated with crepitation, catching and locking sensations. Typically involves young with athletic background. 

There are actually synovial invaginations as a part of remnants of embryological development. They are encountered in MRI over 70% of individuals and are mostly asymptomatic. However these tags can get inflamed secondary to repetitive friction and stretching, making patient symptomatic. They can undergo fibrosis after long standing inflammation imparting them non-stretchable restricting the joint movement and painful.

In symptomatic patients, medial plica seen as low signal intensity band on T1 as well as T2-weighted images with an associated chondral defect involving medial articulating facet of patella.

Treatment is mainly conservative, physiotherapy and intra articular steroid injections.

Leukoencephalopathy, Calcifications and Cysts MRI

Clinically middle age male with history of progressive headache for last 5months.

CT brain shows multiple dense bilateral basal ganglia calcification. 

DDs thought were like Fahrs disease, hypo thyroidism, hypo, pseudo hypo para thyroidism.

However patients thyroid and para thyroid profile was normal and the posterior cranial fossa cyst could not be explained even by Fahrs. With a possibility of a concurrent posterior fossa tumor, patient was referred for MRI brain with contrast.

MRI brain with contrast showed dense calcification in bilateral basal ganglia. The posterior fossa cyst with debris level. No abnormal enhancement along wall of cyst or enhancing eccentric solid nodule depicted on post contrast MRI which ruled out tumor nodule. 

The bilateral symmetric confluent T2 white matter hyper intensity which represents an associated leukoencephalopathy.

Imaging wise primary diagnosis given was LCC. 

Due to mass effect, fourth ventricle compression by the posterior fossa cyst leading to obstructive hydrocephalus, patient underwent posterior fossa craniotomy and excision of posterior fossa cyst was done. Histopathology revealed nonspecific cyst without any tumor cells keeping with MRI diagnosis of LCC. 

LCC or  Labrune syndrome syndrome MRI

Leukoencephalopathy, brain calcifications, and cysts (LCC) also known as Labrune syndrome, an extremely rare with only near  10 cases reported so far in the medical literature.

The condition is caused by homozygous or compound heterozygous mutations in the SNORD118 gene on chromosome 17p13. Clinical presentation varies from spasticity, dystonia, seizures, and cognitive decline.

Etiopathogenesis of LCC is still a matter of debate. Obliterative microangiopathy has been found on histopathological examination as the basic abnormality, the cyst formation is due to necrotic process secondary to obliterative microangiopathy and calcifications is dystrophic in nature. White matter changes result from changes in water content rather than abnormality of myelination.

Another entity which deserves a special mention is cerebro retinal microangiopathy with calcifications and cysts is a distinct genetic disorder due to CTC1 gene problem. Similar leukoencephalopathy, cysts, and calcification have been reported in few cases in association with Coat's disease, described as “Coat's plus. Coat's disease is unilateral retinal telangiectasia with exudation commonly occurring in boys sporadically without systemic features. However, in Coat's plus, there is bilateral retinal telangiectasia with exudation along with systemic features in the form of LCC. 

In my case patient did not have any visual issues so that rules out retinal abnormality and the possibility of cerebro retinal microangiopathy. 

Ears of the lynx sign MRI Brain

Ears of the lynx sign

The ears of the lynx sign refers to an abnormal bilateral symmetric cone-shaped hyperintensity on FLAIR and T2w images at the tip of the frontal horns of lateral ventricles. The abnormality corresponds to the region of forceps minor which resembles the tufts of hair crowning the ears of a lynx. Sagittal T1w images show an associated thin stripe of corpus callosum. 

The sign is typically seen in hereditary spastic paraplegia with thin corpus callosum (HSP-TCC), a form of hereditary spastic paraplegia associated with mutations of the spastic paraparesis gene 11 (SPG11) on chromosome 15. The spatacsin vesicle trafficking associated (SPG11) gene, codes spatacsin. 

The sign may also be seen in SPG15, another of the hereditary spastic paraplegias, which is caused by a mutation in the zinc finger fyve domain-containing protein 26 (ZFYVE26) gene, encoding spastizin. 

This sign has also been described in chronic cases of Marchiafava-Bignami disease.

Isolated Superficial Sylvian Vein Thrombosis MRI

Clinical Details: middle-aged female, altered sensorium after convulsions.

MRI study of brain shows:

Abnormal T2 hyperintensity with marked focal parenchymal swelling due to vasogenic oedema involving left temporal, insular cortex and adjacent opercular parietal white matter. 

Diffusion restriction in corresponding region confined to cortical grey matter of left temporal lobe and adjacent insular cortex on diffusion weighted images. Sub cortical white matter is spared.

 An abnormal leptomeningeal enhancement depicted along left sylvian fissure and in left medial temporal region near cavernous sinus on post contrast MRI. 

Multifocal low signal intensity clustered nodularity demonstrated along left sylvian fissure extending towards cavernous sinus on GRE, which is hyper dense on CT. No abnormal calcification on CT. Normal MR angiography of brain. No obvious aneurysm or high flow vascular malformation on MR angio.

Mass effect, mid brain compression.

Left side Decompressive hemicraniectomy done.

Intraoperative findings revealed thrombosed superficial cortical veins in left sylvian fissure region and at the floor of left middle cranial fossa. 

Final diagnosis: Isolated superficial middle cerebral or Sylvian vein thrombosis.

Superficial middle cerebral vein also known as the Sylvian vein, is one of the superficial cerebral veins. It usually courses along the Sylvian fissure posteroanteriorly and drains numerous small tributaries from the opercular areas around the lateral sulcus. It curves anteriorly around the tip of the temporal lobe and drains into the sphenoparietal sinus or directly into the cavernous sinus. 

Suzuki classification of the superficial Sylvian venous drainage pathways:

1. sphenoparietal type: (54%) drains into the sphenoparietal sinus.

2. emissary type: (12%) courses along the lesser wing of sphenoid, turns inferiorly to reach the floor of the middle cranial fossa, joins the sphenoidal emissary veins, and passes through the floor to reach the pterygoid plexus.

3. cavernous type: (7%) directly drains into the anterior end of the cavernous sinus.

4. superior petrosal type: (2%) runs along the lesser wing and just before reaching the cavernous sinus, turns downward along the anterior inner wall of the middle cranial fossa, then runs along its floor medially to the foramen ovale to join the superior petrosal sinus.

5. basal type: (2%) runs along the lesser wing, turns downward along the anterior wall of the middle cranial fossa, then runs along its floor laterally to the foramen ovale over the petrous pyramid, presumably to join the transverse sinus through the lateral tentorial sinus or superior petrosal sinus.

6. squamosal type: (2%) turns directly backward along the inner aspect of the temporal squama and runs posteriorly to join the transverse sinus or lateral tentorial sinus.

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.

Hahn cleft or canal MRI lumbar spine

 

A linear low signal running transversely in L1 vertebral body through its whole sagittal diameter without marrow odema on STIR.

It's a "Hahn cleft or canal", a normal anatomical variation of no clinical significance and is secondary to persistent nutrient artery and its canal, should not be mistaken for fracture.