Woo Gyeong Kim, Brendan Morrison.

 

Background: Xanthogranulomatous epithelial tumour is a recently revealed rare neoplasm with predominantly foamy histiocytic xanthogranulomatous inflammation and giant cells with obscured scattered bland, eosinophilic keratin-expressing epithelial cells.

Case Presentation: We report a case of a xanthogranulomatous epithelial tumour on right groin of a 64 years old man who underwent excisional biopsy. Macroscopically, a 3cm sized ruptured cystic lesion with yellow solid content was observed in subcutis. Microscopically, a well circumscribed nodular lesion confined in a fibrous capsule was present containing proliferation of diffuse sheets of foamy histiocytes, giant cells of touton and osteoclast-like types and admixed with chronic inflammatory cells. There were distinctive brightly eosinophilic bland looking cells scattered within the lesion which were proven to be epithelial origin as cytokeratin AE1/AE3 and cytokeratin 7 immunohistochemical stains  demonstrated strong expression whereas histiocytic and mesenchymal markers were negative.

Conclusion: Xanthogranulomatous epithelial tumour is a rare entity with a deceptive histologic findings as the origin of the scattered epithelial cells within the lesion are easily obscured. Although the natural history has been mostly reported to be indolent, thorough studies with a large sample size and adequate follow-up are mandatory due to limited data available.

1. Svantesson T, van Oudenaarde K, Vogestseder A, et al. Xanthogranulomatous epithelial tumour: A novel entity of uncertain biologic potential. Arch Clin Cases 2023; 10(3): 142-145.

2. Dehner CA, Baker JC, Chrisinger JSA, et al. Xanthogranulomatous epithelial tumours and keratin-positive giant cell-rich soft tissue tumours: two aspects of a single entity with frequent HMGA2-NCOR2 fusions. Modern Pathology 2022; 35: 1656-1666.

 

Contribution: WGK contributed to writing this manuscript and BM conducted ancillary studies and made final diagnosis of this case. All authors reviewed the abstract.  

 

 

I declare that the following statements are true to the best of my knowledge with regard to the submission of this abstract. 

1. I am the person who wrote this abstract originally.

2. I agree to submit this abstract to the Pathology Update 2025 conducted by Royal College of Pathologists Australasia. 

3. I certify that this is the original abstract. It has not been previously published and is not currently under submission in other competition or elsewhere.

Sign: 

Name: Woo Gyeong Kim

Date: 21/10/2024