Langerhans cell histiocytosis

Findings and interpretation:

Chest radiograph:

• The lungs are hyper-inflated, with diffuse reticular opacities and a few scattered irregular nodules.

HRCT:

• There are widespread thin walled cysts of varying shapes and sizes, with an upper lobe distribution, that almost replace the lung parenchyma bilaterally.
• There are a few scattered irregular nodules in both lungs, predominantly in the upper lung zones.

Pertinent negative findings:

• There are no areas of ground glass opacification / consolidation in the lungs.
• There are no focal lesions in the visualised bones of the thorax.

The findings represent an interstitial, cyst forming disease of the lung.

Principal diagnosis:

Langerhans cell histiocytosis

Differential diagnosis:

• Pulmonary lymphangioleiomyomatosis

Management:

Alert physician of findings and recommend respiratory physician referral.

Recommend discussion at pulmonary MDT with regards to confirming diagnosis by tissue biopsy / further management by lung transplant.

Neutropaenic colitis

Findings and interpretation:

• There is diffuse thickening of the bowel wall, involving long segments of small and large bowel. Mucosal hyperenhancement with hypo-attenuating of the muscularis layer is noted. The right side of the colon shows a greater degree of involvement than the remaining affected bowel.
• There is a large degree of mesenteric and peri-colic fat stranding.
• There is a large amount of ascites, with thickening and enhancement of the peritoneum at multiple sites.
• There are foci of extraluminal gas in the left flank, signifying a small, focal bowel perforation.
• Bilateral large pleural effusions with adjacent segmental basal lung atelectasis.

Stratified enhancement of the bowel indicates muscularis oedema. The findings reflect inflammation of small and large bowel, as well as the peritoneum. Greater involvement of the right side of the colon is characteristic of neutropaenic colitis.

Principal diagnosis:

Neutropaenic colitis with associated peritonitis.

Differential diagnosis:

• Different infectious colitis, such as cryptosporidiosis, giardiasis, etc..
• Pseudomembranous colitis (unlikely as does not involve small bowel).

Management:

• Alert referring physician of findings.
• Discussion with interventional radiology regarding possibility of peritoneal drain insertion.

Lung carcinoma with haemorrhagic brain metastases and incidental pleomorphic adenoma

Findings and interpretation:

Chest radiograph:

• There is a large, central mass in the right lung, projected over the right hilum.

Ultrasound parotid:

• There is a well defined, heterogeneously hypoechoic lesion in the right parotid gland, showing posterior acoustic enhancement. It shows mild internal colour doppler signal.

CT brain:

• There is a moderate sized region of intra-parenchymal acute haemorrhage hyperdensity in the left occipital lobe, with mild surrounding hypodensity indicating cerebral oedema.
• There is a well defined, heterogeneously hypodense lesion at the anterior aspect of the right parotid gland.

Pertinent negative findings:

• There is no significant intracranial mass effect.
• There is no right cervical lymphadenopathy.

The findings represent focal cerebral haemorrhage, as well as a likely neoplastic mass in the left lung. The haemorrhage is likely originating from a cerebral metastasis from the lung primary.

The parotid lesion shows benign characteristics and is likely an incidental, benign lesion.

Principal diagnosis:

Lung carcinoma with haemorrhagic brain metastasis and incidental pleomorphic adenoma.

Differential diagnosis:

• Unrelated cerebral haemorrhage and lung carcinoma

Management:

• Alert referring physician of findings.
• Recommend staging CT thorax/abdomen/pelvis.
• Refer for oncology MDT discussion with regards to image guided tissue biopsy from appropriate source following further radiological examinations.

Sub-ependymal giant cell astrocytoma

Findings and interpretation:

CT:

• There is an ill-defined, intraventricular soft tissue mass, intimately related to the left aspect of the septum pellucidum.
• The mass is located at the foramen of Monro, and protrudes into the left lateral ventricle.
• There is an adjacent calcified sub-ependymal lesion.
• The mass shows avid heterogeneous post-contrast enhancement.
• The mass is causing compression of the third ventricle by mass effect, with subsequent asymmetrical marked dilatation of the lateral ventricles.
• Generalised supratentorial sulcal effacement.

MRI:

• The mass is heterogeneously hyperintense on FLAIR images, with a multi-cystic component inferiorly. There is surrounding periventricular white matter FLAIR hyperintensity.
• There is avid, heterogeneous post-contrast enhancement.

Pertinent negative findings:

• There are no other intra / extraventricular intracranial lesions.
• There are no parenchymal lesions/altered signal to suggest cortical tubers.

The findings represent a single intraventricular neoplasm with non-aggressive features. This is causing obstruction at the level of the third ventricle with obstructive hydrocephalus.

Principal Diagnosis:

Sub-ependymal giant cell astrocytoma

Differential diagnosis:

• Intraventricular meningioma
• Intraventricular metastasis (unlikely given the patient’s age)
• Central neurocytoma (unlikely as this typically has a multi-cystic appearance)
• Supratentorial ependymoma (unlikely as this typically has more aggressive features)
• Choroid plexus papilloma (unlikely as this is not the location of the choroid plexus)

Management:

Alert referring physician of diagnosis.

Recommend discussion at neurology/neurosurgery MDM.

Pigmented villonodular synovitis

Findings and interpretation:

• There is a moderate sized knee joint effusion.
• The knee joint synovium around the effusion shows nodular thickening and forms nodules and frond-like masses that project into the effusion. These show low signal intensity on both T1 and proton density weighted sequences.
• On the gradient echo sequence, the synovium and synovial nodules and masses show blooming artefact, indicating haemosiderin deposition.

Pertinent negative findings:

• No evidence of erosion at the articular surfaces.

The findings represent benign thickening and proliferation of the synovium, which has undergone repeated haemorrhage.

Principal Diagnosis:

Pigmented villonodular synovitis.

Differential diagnosis:

• Haemophilic arthropathy (this typically shows a greater degree of erosion, as well as epiphyseal overgrowth).

Management:

• Alert referring physician of diagnosis. Recommend orthopaedic referral.
• Biopsy may be performed for histological diagnosis.
• This is usually treated by synovectomy.

Necrotizing pneumonia with bronchopleural fistula

Findings and interpretation:

• The left lower lobe is collapsed, with multiple pockets of gas within the collapsed lobe of varying size and shape.
• There are non-enhancing regions of lung parenchyma within the collapsed lobe.
• There is a large, loculated pleural effusion containing fluid and air (air-fluid level noted).
• There is a peripheral, subsegmental consolidation in the left upper lobe.

Pertinent negative findings:

• No significant mediastinal lymphadenopathy.

Incidental findings:

• Hypodense liver lesions in the left lateral segments, which are non-specific in appearance.

The findings reflect a process in the lung causing necrosis; this is associated with a loculated hydropneumothorax, due to communication between the bronchial tree and the left pleural space caused by breakdown of necrotic lung parenchyma.

Principal diagnosis:

Necrotizing pneumonia with bronchopleural fistula.

Differential diagnosis:

• Necrotizing lung mass (malignancy); this is unlikely as there is no discrete mass detected.

Management:

• Contact referring physician urgently and inform of findings.
• Recommend interventional radiology opinion for possibility of pleural drainage.