Today’s case is a 12-year-old female spayed Siamese cross with several weeks of increased difficulty breathing. Take a look and post your interpretations.
Findings
Radiographs: There is a soft tissue mass in the cranial mediastinum as well as in the dorsal portion of the mid thorax causing ventral and caudal displacement of the tracheal carina. There is also severe atelectasis of all lung lobes. There are multifocal patchy infiltrates within all the lung lobes as well. The cardiac silhouette cannot be identified. The margins of the diaphragm can also not be identified clearly. The right 10th – 13th ribs are fractured with minimal displacement.
Ultrasound: There is a large heterogenous infiltrative mass in the dorsal mediastinum, which is surrounding the aorta and esophagus, and adjacent to the heart and diaphragm.
Diagnosis
Cryptococcosis.
Necropsy: There is an approximately 15 x 8 x 6 cm globoid gray-tan, slightly mucoid, friable mass that extends from the thoracic inlet to the diaphragm, slightly displaces the lungs and surrounds the aorta. There are multifocal variably sized (pinpoint -2.5 cm) tan – yellow firm slightly depressed foci with dark red raised edges (umbilicated) on the surface of the lungs. These extend into the parenchyma on cut surface. There is cloudy yellow viscous exudate within the lumen of the trachea.
Great case. Have you ever before seen such mediastinal lesions with cryptococcosis? I have only previously heard of the URT disease. Was this considered to be some kind of extension from a mediastinal lymphadenopathy (i.e a severe granulomatous lymphadenitis with caseous necrosis)? Purely from an imaging perspective would you have included other differential diagnoses such as paraoesophagheal tumours or chemodectoma? Thanks.
Yes, I think this was lymphadenopathy with extension throughout the mediastinum. I suspect this would be due to immune compromise as the disease is usually more limited as you said. I would include other mediastinal lesions in the differential list as well.