Pulmonary cryptococcosis

Case contributed by Dr Jörgen Strömberg

Presentation

Patient with a history of smoking since 20 years. He was also known with a chronic neurological disease and repeated episodes of bowel obstruction due to previous surgery. At one of these episodes, a CT abdomen was performed and a pulmonary nodule incidentally found.

Patient Data

Age: 50's
Gender: Male
CT

Initial detection

In the dorsal aspect of the left lower lobe, a 9 mm pulmonary nodule is detected. It cannot be seen on any previous examinations.

The finding of the pulmonary nodule resulted in a follow up examination of the thorax, that was carried out two months later.

CT

1st follow up (2 months)

At this follow up, the pulmonary nodule has changed characteristics from a solid nodule to more of a ground glass appearance. The size has increased from 9 to 14 mm. In addition, there is also a 6 mm pleural nodule located somewhat more apical and medial to the ground glass nodule. It is uncertain if this nodule is new, since the previous examination did not include the entire thorax.

The fact that the lesion was growing and that the patient had a heavy history of smoking called for further workup. In this case, the patient was referred to PET-CT that was carried out six weeks later (in total 3½ months from the initial detection).

Nuclear medicine

PET-CT (3½ months after initial detection)

The pulmonary nodule shows no change since the previous examination. There is no increase in FDG-uptake on the PET-scan. 

The absence of FDG-uptake does not rule out malignancy, as a slowly progressing adenocarcinoma might be void of uptake. A conservative approach with further CT followups was chosen.

CT

2nd follow up (11 months after initial detection)

This CT was carried out 7 months after the PET-CT (in total 11½ months after initial detection of the lesion). The nodule has yet again changed characteristics. It now appears solid with a spiculated contour, giving it a clearly tumour-like appearance. The size has increased further to 16 mm.

The small pleural nodule apical and medial to the lesion has not changed since it was first detected.

After this development, the case was discussed with pulmonologists and thoracic surgeons. Since it was highly suspected that the lesion represented a tumour, it was decided that the patient undergo a left lower lobectomy. 

The pathology report of the specimen concluded that there were no mailgnant cells. Instead, findings were consistent with a necrotizing granulomatous inflammation. Further investigation revealed precense of fungus (cryptococcus neoformans).

Case Discussion

This case, which includes multiple consecutive CT examinations of a lesion ultimately proven to be a solitary pulmonary cryptococcosis infection, demonstrates the spectrum of radiological appearances that such a focus can cause. Furthermore, it serves as an illustration of the diagnostic challenge this specific infection poses - both to the radiologist and the clinician.

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Case information

rID: 46121
Case created: 22nd Jun 2016
Last edited: 21st Jan 2017
System: Chest
Inclusion in quiz mode: Included

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