Case Study: April 2009

History

A 60 year old man presents with an amelanotic mass in the posterior choroid.
The clinical diagnosis is that of malignant tumour ? melanoma ? metastasis.

A trans-vitreal aspirate is performed of the choroidal tumour.

Figure 1 and 2 show the H&E figures of pieces of solid tissue that were aspirated (cell block preparation).

Figure 3 is an AE1 AE3, Figure 4 is a prostate acid phosphatase and Figure 5 is a Melan A.

Questions

1. What do Figures 1 and 2 show?
2. Which additional investigations can be performed?
3. What is the likeliest diagnosis in this case?

Click to show answers
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1. Cohesive clusters of cells with an epithelioid morphology, bereft of melanin pigment, The nuclei are monotonous with some eosinophilc nucleoli. The cytoplasm has a bubbly appearance. Spindle cells do not feature.

2. Immunohistochemistry with melanocytic and epithelial markers.

3.The tumour is metastatic prostatic carcinoma to the choroid. The patient had a history of prostatic ductal adenocarcinoma, diagnosed on needle biopsies of the prostate.

References

Uveal metastasis from prostate carcinoma. De Potter P, Shields CL, Shields JA, Tardio DJ. Cancer. 1993 May 1;71(9):2791-6.