Case Study: September 2015


A 50-year-old male with recent onset asthma develops a non-axial proptosis of the left side. His blood profile shows a slightly raised eosinophil count but is otherwise OK. He undergoes a biopsy of the mass.


1. What is seen in Figs 1 and 2?

2. What is seen in the centre of Fig 3?

3. What does Fig 4 show?

4. This is a CD68 stain. What other stains should be utilised when working up this type of case?

5. What is the differential diagnosis?

Click to show answers


1. Fomay cells-histiocytic between the extraocular muscle fibres.

2. Touton giant cell.

3. A recative lymphoid aggregate.

4. Pan-cytokeratin to exclude metastatic clear cell carcinomas, PAS for Whipple’s, ZN for mycobacteria.

5. The differential includes:

AOX-Adult onset xanthogranuloma

AAPOX-adult onset asthma and periocular xanthogranuloma

NBX-necrobiotic xanthogranuloma

ECD-Erdheim Chester disease.

Xanthogranulomatous variant IgG4 disease.

In this case the diagnosis was AAPOX.