Look for the silent when other tests cannot speak (a case of unexpected rare thalassaemia)

Pathology (2011) 43(S1), pp. S70–S84

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CLEAR CELL SARCOMA-LIKE TUMOUR OF THE GASTROINTESTINAL TRACT CAUSING SMALL BOWEL OBSTRUCTION IN A YOUNG WOMAN S. Al Jahdhami, M. Lui Anatomical Pathology, ACT Pathology, The Canberra Hospital, Woden, ACT Australia A 26-year-old woman with a history of Hodgkin’s lymphoma in remission, presented with abdominal pain and vomiting. Abdominal CT scan showed signs of small bowel obstruction associated with a localised area of intestinal wall thickening and mesenteric lymphadenopathy. Macroscopic examination of the resected small bowel showed a 2 cm stricturing and ulcerating tumour. Histology revealed a transmurally invasive malignant neoplasm composed of sheets and nests of epithelioid clear cells, with high-grade cytology and dispersed osteoclast-like giant cells. Immunohistochemically, the tumour cells were positive for S100 and negative for Melan-A, HMB45, pancytokeratin, desmin and c-kit. Electron microscopy showed no diagnostic features. Fluorescence in situ hybridisation (FISH) analysis of the tumour confirmed EWSR1 gene rearrangement with t(12,22). These features are consistent with a clear cell sarcoma-like tumour of the gastrointestinal tract (CCSLTGT). Post-operatively, the patient developed adhesions but was otherwise well. CCSLTGT is a recently described new tumour entity that shares some but not all features of clear-cell sarcoma of soft parts. It is exceedingly rare, mainly affects young adults and tends to behave aggressively. The presence of osteoclast-like giant cells and isolated tumoural expression of S100 protein, coupled with EWSR1 translocation, are defining features. Diagnosis of this tumour as a metastatic malignant melanoma is a potential pitfall. WELL DIFFERENTIATED NEUROENDOCRINE CARCINOMA OF THE PANCREAS WITH ULTRASTRUCTURAL FEATURES OF INSULINOMA S. Al Jahdhami, M. E. Koina, S. Jain Anatomical Pathology, ACT Pathology, The Canberra Hospital, Woden, ACT, Australia A 73-year-old woman presented with abdominal pain radiating to the back associated with vomiting and weight loss. Blood glucose was initially normal. CT scan revealed a 2 cm tumour in the body of the pancreas. Histopathological examination of the distal pancreatectomy specimen revealed a well differentiated neuroendocrine carcinoma with a predominantly insular and focally trabecular growth patterns. The tumour cells displayed moderate nuclear pleomorphism and coarse chromatin patterns. Up to 2 mitoses/10 HPF were observed. There was direct invasion of two adjacent lymph nodes. Immunohistochemically, the tumour showed positive staining for pan-neuroendocrine markers and negative staining for glucagon, somatostatin and Print ISSN 0031-3025/Online ISSN 1465-3931 DOI: 10.1097/01.PAT.0000394567.34034.ee

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gastrin (insulin immunostain was not available). Ki-67 was positive in 5–6% of tumour cells. Electron microscopy revealed dense-core neurosecretory granules, many of which exhibited characteristic ‘squared-off’ crystalline forms, typically seen in beta-cell differentiation/insulinoma. Post-operatively, the patient developed diabetes, a known sequelae of distal pancreatectomy. Insulinomas are rare with an incidence of 2–4 patients/million population/year. They are the most common functioning pancreatic neuroendocrine tumours (NETs) and tend to occur between 40 and 60 years. Between 7% and 10% of cases are malignant. The European NET Society recently designed and approved a TNM staging proposal for foregut and pancreatic NETs, as well as suggested criteria for grading them based on mitotic count and Ki-67. LOOK FOR THE SILENT WHEN OTHER TESTS CANNOT SPEAK (A CASE OF UNEXPECTED RARE THALASSAEMIA) L. Al-Zadjali, L. Coyle PaLMs, Royal North Shore Hospital, Sydney, NSW, Australia Microcytic anaemia is a common consultation in haematology practice. The common causes are iron deficiency, thalassaemia or anaemia of chronic disease. The diagnosis can be directly obtained through appropriate laboratory tests. However, in the absence of a positive history or a laboratory test, the diagnosis may be obscure and more sophisticated laboratory tests may be required. A 27-year-old Australian woman from a Scottish-Welsh ancestry was referred with long standing microcytic anaemia. The laboratory tests including iron studies, haemoglobin HPLC and electrophoresis were normal and repeated twice to exclude pre-analytical and analytical variability. Other causes of microcytic anaemia including lead toxicity, copper or zinc deficiency, chronic inflammatory disease or sideroblastic anaemia were excluded. The patient’s blood sample was sent to the Royal Prince Alfred hospital for molecular testing for possible underlying thalassaemia. A heterozygous large deletion in the beta globin region with an intact alpha globin using DNA sequencing and multiplex ligationdependent probe amplification (MLPA) was detected. The finding supports the diagnosis of epsilon-gamma-delta-beta (egdb)o thalassaemia. This type of normal HbA2 beta thalassaemia or silent beta thalassaemia has been previously reported in a family with Scottish-Irish ethnic background in NSW.1 Reference 1. Trent RJ, Williams BG, Kearney A, et al. Molecular and hematologic characterization of Scottish-Irish type (epsilon gamma delta beta)zero thalassemia. Blood 1990; 76: 2132–8.

Ki67 EXPRESSION IN OESTROGEN RECEPTOR POSITIVE BREAST DUCTAL CARCINOMA E. Amini, R. Au, D. S. Williams Department of Anatomical Pathology, Austin Pathology, Austin Hospital, Heidelberg, Vic, Australia

2011 Royal College of Pathologists of Australasia

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