Spectator

5 year old patient with 1 week of right eye blurry vision, then several days of right eye pain. Physical exam notable for right papilledema and progressively worsening vision.

MRI postcontrast through the orbits shows an enlarged, hyperenhancing right optic nerve (red arrow) compared to the normal left side (green arrow), compatible with optic neuritis.

A lumbar puncture was performed: no oligoclonal bands, no aquaporin 4 IgG, positive anti-MOG. The patient was treated with prednisone with return to normal vision a few months later.

Final diagnosis: optic neuritis from myelin oligodendrocyte glycoprotein​ antibody-associated disease (MOGAD).

This patient had episodic electric/shooting/radiating pain of the left face. An MRI was done.

[Top]: Axial heavily T2-weighted image (bright = CSF, dark = not CSF) at the level of trigeminal nerve (cranial nerve V / CN5), shows a normal right CN5 (green). The left CN5 seems to be splayed out by another tubular structure (red), which is the superior cerebellar artery (SCA).

[Bottom Left]: Sagittal reconstruction of the normal right CN5 (along the blue line).

[Bottom Right]: Sagittal reconstruction of the left CN5 shows the left SCA contacting the left CN5. The close proximity of the left SCA and its arterial pulsations likely irritate the cranial nerve, which is the primary sensory nerve of the face, causing trigeminal neuralgia.

Incidental finding of a superior lumbar hernia (Grynfeltt-Lesshaft hernia). In this case, only a lobule of retroperitoneal fat is herniating through the defect, but organs can also herniate through.

Continuing the theme of things extending into spaces they don't belong in, this is an incidental finding of an inguinal hernia that contains a small portion of the bladder. The patient got the CT for other reasons.

Bowel into inguinal hernia causing bowel obstruction.

Appendix into inguinal hernia, incidental finding.

Ventriculoperitoneal shunt into inguinal hernia, incidental finding.

[LEFT]: This patient had one of the longer cerebellar tonsillar herniations I've seen. The tonsil is peg-like in shape and extends quite far below the foramen magnum to the level of the C2 posterior arch. As a result, there is crowding at the foramen magnum that is enough to impede CSF flow, resulting in hydrocephalus with dilated ventricles. Partly seen in the cervical cord from C2 and below is a syrinx, an associated finding. Chiari I is thought to be due to not enough space provided for the cerebellum by the calvarium or skull base shape, causing it to herniate into the spinal canal and cause trouble.

[RIGHT]: A comparison normal from online for you to compare the cerebellar tonsils.

[LEFT]: The midbrain has a deep interpeduncular cistern, and the superior cerebellar peduncles are very prominent and elongated, making the brainstem at this level look like a molar tooth. This is a classic finding in Joubert syndrome.

[RIGHT]: A comparison "normal" midbrain. However, this patient's brain is not normal at all. Can you find the abnormalities?

Female in her 30s with painful left shoulder.

[Left]: X-ray shows a mass arising from the left proximal humerus and extending into the adjacent shoulder soft tissues with really aggressive periosteal reaction ("hair on end"). The proximal humerus itself is also heterogeneous with lucent areas. The lateral surface of the upper humerus shows "saucerization," where the cortex is thinned out and looks like a saucer seen on edge.

[Middle]: MRI IR sequence shows a hyperintense bony mass with large soft tissue component.

[Right]: MRI postcontrast T1 IDEAL shows that the mass is enhancing.

This turned out to be high-grade surface osteosarcoma.

33 year old female with abdominal pain, abdominal distention, nausea/vomiting, early satiety, and weight loss.

Bottom right: Ultrasound done in a panorama shows how distended the abdomen is by a large multi-cystic mass.

Top right: Non-panoramic ultrasound image shows how limited the imaging modality is in being able to cover such a large mass. This image also shows a more solid area within the mass.

Left: CT images approximately where the ultrasound was done.

The patient underwent laparotomy with removal of the ovarian, fallopian tube, and appendix. There was a large ovarian cyst that was draining serous fluid (watery), mucinous fuid (mucus-like), and blood. The final path was as titled.

Postcontrast imaging of 2 patients with glioblastoma. These tumors are notorious for spreading along the white matter tracts - in this case the transverse fibers of the corpus callosum, given them a classic "butterfly" appearance.

Two different patients with genetic disorders resulting in overgrowth of the brain.

These represent mutations in cell cycle and cell metabolism genes that lead to larger cells and/or more cells. These types of disorders tend to have mosaicism of some form, which is to say some cells have the mutation active while others don't. The distribution of these cells can be very geographic/regional - in these two cases, one hemisphere of the brain is involved.

Compare this against a previous case with hemispheric atrophy.

Quick one today. Take a look at Patient A and Patient B.

Patient A has a smooth focal indentation of the posterior cervical esophagus.

Patient B has a broader indentation that is also irregular and nodular along its contour.

Patient A has a cricopharyngeal bar, which is a prominence caused by the cricopharyngeus muscle that can cause dysphagia if it gets really prominent. Patient B has esophageal squamous cell carcinoma.