1. What are the relevant xray signs?
2. What is the differential diagnosis?
3. What is the next test of choice and how would it help?
An important point to note on this CXR is that the lung volumes are preserved. There is lateral peaking of the right hemidiaphragm, and adjacent to this there are staples in the right lower zone. There is a reticulonodular pattern of opacification but no airspace opacification.
The differential diagnosis is of a lung volume preserving chronic interstitial lung disoreder: i.e. between Langerhans cell histiocytosis and lymphangiomyomatosis.
The next step is a high resolution CT (HRCT) of the thorax:
This CT indicates a predominant cystic pattern, with bizarre and odd shapes to the cysts. A few nodules are seen. Elsewhere on the CT, the bases were spared. She had previously had an open biopsy, this accounts for the staples and the minor hemidiaphragm peaking seen on the CXR.
The diagnosis is Langerhans cell histiocytosis (LCH).
Key learning points:
- early in the disease nodules predominate, later it is cysts
- typical demographic: 20-40 year old females
- sparing of extreme bases
- lung volumes preserved
- bizarre shape to cysts (round and regular in LAM)
#xrayoftheweek #FOAMRad #FOAMed