Fiona Maclean

Atypical EWSR1 FISH signal patterns in bone and soft tissue tumours:– diagnostic experience with 135 cases

Recurrent Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangements characterize a select group of bone and soft tissue tumours. In our routine diagnostic practice with fluorescence in‐situ hybridization (FISH), we have occasionally observed EWSR1 gene rearrangements in tumours not associated classically with EWSR1 translocations. This study aimed to review our institutional experience of this phenomenon and also to highlight the occurrence of unusual EWSR1 FISH signals (i.e. 5′ centromeric region or 3′ telomeric region signals) that do not fulfil the published diagnostic criteria for rearrangements.

FISH analysis of selected soft tissue tumors: Diagnostic experience in a tertiary center

Fluorescence in situ hybridization (FISH) is an important ancillary tool for the classification of bone/soft tissue (BST) tumors. The aim of this study was to evaluate the contribution of FISH to the final classification of common BST entities in the molecular pathology department of the Royal Prince Alfred Hospital (RPAH), which is one of the most important referral centers for the management of sarcomas in Australia.

48. An unusual presentation of Angiomatoid Fibrous Histiocytoma (AFH)

AFH accounts for 0.3% of all soft tissue tumours and typically affects the extremities of children and young adults. Classically, microscopically, fascicles and sheets of oval to spindle cells, pseudovascular spaces, haemorrhage and a fibrous pseudocapsule rimmed by a lymphocytic infiltrate are noted. However, some cases lack these typical features, often bearing a striking resemblance to organising haematoma. Recently, cytogenetic analysis of AFH has shown specific translocations involving the EWSR1 and FUS genes. We document a seventy-one year old man who presented with a recurrent lesion of the left triceps muscle, six years after surgical excision. The radiology, morphology and immunohistochemical profile (EMA, desmin negative) of the initial lesion were those of an organising haematoma. (The lesion was completely embedded). It’s true nature was only revealed at recurrence, where characteristic histological and immunohistochemical features of AFH were noted, prompting cytogenetic evaluation of both lesions. The EWSR1 rearrangement was present in the initial and recurrent lesion. Therefore, whilst morphological and immunohistochemical evidence of AFH were not present initially, recent cytogenetic advances have enabled confirmation of AFH at that time. This case illustrates the utility of cytogenetic testing in the diagnosis of AFH where the lesion deviates from the classical histological appearance. This possibility should be considered in haematomas in the absence of a specific cause at any age.

Update on renal tumours

This presentation will give an update on renal tumours encompassing new entities [including tubulocystic renal cell carcinoma (RCC), acquired cystic disease associated RCC, clear cell tubulopapillary RCC, t(6;11) translocation carcinoma, and hereditary leiomyomatosis and RCC] and emerging entities [thyroid-like follicular RCC, succinate dehydrogenase B (SDHB) mutation associated RCC, and ALK-translocation associated RCC]. A summary of the entities accepted in these categories by consensus at the International Society of Urological Pathology meeting in Vancouver in March 2012 will be given. Discussion of important familial tumours involving the kidney will be included.

How to report renal tumours

During this presentation there will be discussion of both macroscopic and microscopic features important to include in reports pertaining to renal tumours, and common difficulties and misconceptions such as the renal sinus will be considered and identified. Use of synoptic reports will be discussed, as will the consensus decisions coming out of the International Society of Urological Pathology meeting in Vancouver in 2012, including the change to grading of renal cell carcinomas.

RCPA quality assurance program: review of the urology module

In the course of the presentation a review of the urology module of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP) will be made, including an assessment of the results pertaining to straightforward urogenital cases, and those that presented more of a challenge to respondents. One aspect that will be examined in more depth is the range of responses given in regard to Gleason scoring of prostate adenocarcinoma, an area that has not been formally assessed to date but will be assessed going forward. Discussion will also be made concerning the performance monitoring project and the framework to be introduced in regard to anatomical pathology.