Clarence Hai Yi Teo

Fasciola hepatica in a New Zealander Traveler

Fascioliasis is a reemerging zoonosis endemic in many parts of the world. Reports of imported fascioliasis by migrants into nonendemic countries are common, but tourists and business travelers are rarely afflicted. Here, we report a case of a New Zealander traveler who acquired the infection on a business trip.

Tracheal carcinoma ex pleomorphic adenoma: a rare tumour with potential problems in diagnosis.

CLL with 17p deletion in our patient without EBV infection or prior fludarabine therapy. The pathogenesis in our patient is unclear and questions the use of the term Richter’s transformation for describing aggressive lymphomas arising in CLL ⁄ SLL that are molecularly distinct. The expression of CD5 in H-RS cells noted in our case has not been reported in previous cases of the HL variant of Richter’s transformation, although de novo HL has been known to express many T-cell antigens, CD2 and CD4 in particular. The B-cell genotype of H-RS cells and their clonal distinction from CLL ⁄ SLL cells suggest CD5 expression in the former is aberrant and cannot be used to infer a common clonal origin of the two neoplastic populations. In summary, our case adds to the literature on transformation of CLL ⁄ SLL to HL, which is a rare variant of Richter’s syndrome, and supports the hypothesis that the latter is a second neoplasm rather than clonal evolution of SLL.

Thyroid transcription factor-1 may be expressed in ductal adenocarcinoma of the prostate:a potential pitfall

We report a case of prostatic ductal adenocarcinoma which expressed thyroid transcription factor-1 (TTF-1) on immunohistochemical examination, and highlight the fact that this aberrant staining is a potential pitfall in the evaluation of this lesion. Prostatic core biopsy specimens from a 65-year-old man revealed an adenocarcinoma with large-calibre glands lined by stratified hyperchromatic nuclei. There was no accompanying conventional acinar adenocarcinoma and TTF-1 was distinctly positive in the nuclei of the malignant cells. This led to a search for possible lung and other primaries. When a thorough systemic investigation disclosed no evidence of other primary tumours, a radical prostatectomy was performed which revealed predominant ductal adenocarcinoma with a minor component of acinar adenoarcinoma. TTF-1 measurement was repeated which showed staining confined to the ductal adenocarcinoma. Prostate specific antigen (PSA), PSAP and racemase were also found. Our findings underscore the increasing spectrum of lesions that may express TTF-1 on immunohistochemical examination. TTF-1 is part of a family of homeodomain transcription factors with restricted expression in the thyroid and lung.1–3 Its immunohistochemical detection has been used in diagnostic surgical pathology to distinguish thyroid and lung tumours from those of other organs.4,5 Specifically, antibodies to TTF-1 have been reported to be useful in distinguishing pulmonary adenocarcinoma from other primary carcinomas.6 TTF-1 is expressed by differentiated thyroid neoplasms.7 It can assist in the differential diagnostic investigation of mesothelioma from pulmonary adenocarcinoma, small cell lung carcinoma from Merkel cell carcinoma,2,3 and neuroendocrine tumours of the lung from well-differentiated neuro-endocrine tumours at other sites.1,8 TTF-1 mRNA has been discovered in orbital tissues,9 C cells and parathyroid cells.10 More recently, nuclear TTF-1 protein expression was reported in primary and metastatic colonic adenocarcinoma,11,12 primary ovarian epithelial neoplasms,13 thyroid-like nasopharyngeal papillary adenocarcinoma,7 gastric …

CD99 negative primary sciatic nerve Ewing family tumour in a middle-aged woman: a rare clinical presentation

Sir, Ewing family tumours (EFTs) comprise a group of morphologically heterogeneous small round cell tumours (SRCTs) characterised by a non-random chromosomal translocation involving the Ewing’s sarcoma (EWS) gene and one of several members of the ETS family of transcription factors. A presentation as a primary peripheral nerve tumour lacking CD99 expression is rare, and this case illustrates the importance of corroborating molecular techniques with the clinical, light microscopic and immunohistochemical findings in establishing a correct diagnosis given the unusual clinical context. To the best of our knowledge, this is the first reported case of a primary peripheral nerve EFT where the application of fluorescent in situ hybridisation (FISH) was pivotal in the diagnosis. A previously healthy 39-year-old Malay female was admitted in April and August 2004 and April 2005 for severe, sharp pain over the left posterior thigh radiating to the left foot, which resolved with analgesia after a period of observation during the first two admissions. There was no history of trauma, back pain, bowel and urinary incontinence, or constitutional symptoms. A magnetic resonance imaging (MRI) scan of the lumbar spine performed during her first admission was normal. Although treated symptomatically as for a back strain, the pain became progressively worse in the few months before her third admission. Physical examination and electromyography showed features consistent with a left sciatic peripheral neuropathy, in addition to a tender mass in the posteromedial aspect of the left thigh. A MRI scan revealed an ill-defined, 86464 cm fusiform mass arising from the left sciatic nerve, with displacement of the surrounding muscles (Fig. 1). A biopsy with intra-operative frozen section was performed in July 2005 at another institution. A subsequent bone scintigraphy and computed tomography (CT) scan of the thorax

Soft tissue chondroma mimicking ''dumbbell'' neurogenic tumour: A rare cause of lumbar radiculopathy

Soft tissue chondromas are rare, benign extra-skeletal tumours of cartilaginous origin, which may rarely occur within the spinal canal. We report a patient who presented with left lumbar radiculopathy, and a peripherally-enhancing dumbbell shaped soft tissue mass involving both the intraspinal and extraspinal compartments on MRI. This was misdiagnosed as a neurogenic tumour and the patient underwent surgical removal. Histological examination revealed cartilaginous tissue. Although rare, soft tissue chondromas should be considered in the differential diagnosis of spinal dumbbell shaped tumours, especially if MRI shows peripheral contrast enhancement.

Extramedullary haematopoiesis in axillary lymph nodes and breast parenchyma in breast cancer treated with neoadjuvant chemotherapy: a potential diagnostic pitfall

Extramedullary haematopoiesis is rarely seen in the breast parenchyma and axillary lymph nodes in the setting of neoadjuvant chemotherapy, with intrinsic and extrinsic factors hypothesised as causes for this phenomenon. Documenting the response of the invasive carcinoma to the preceding chemotherapy is an important part of the pathological examination, which has implications to the prognosis and treatment algorithms of these patients. An increased awareness of this uncommon and yet important phenomenon of extramedullary haematopoiesis in such a setting is pivotal in avoiding a misdiagnosis. Here we report the occurrence of extra-medullary haematopoiesis in the axillary lymph nodes and breast parenchyma of a 45-year-old female patient who had undergone neoadjuvant chemotherapy for locally advanced breast cancer, which was previously reported as an invasive ductal carcinoma. On histology, there was no residual carcinoma; however, subtle foci of tri-lineage haematopoiesis were seen both within the breast parenchyma and multiple lymph nodes, especially within the capsule and sinuses of the latter. Although rare, this phenomenon may potentially mimic a primary breast carcinoma, particularly an invasive lobular carcinoma as well as residual breast cancer. The histological criteria and use of immunohistochemistry stains as an adjunct in separating extramedullary haematopoiesis from malignancy is presented.