Biomedical subjects
Joon Joon Khoo
Publications and source records attributed to Joon Joon Khoo.
Infantile primary hyperoxaluria type 1 with end stage renal failure.
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A clinical and immunohistochemical study of gastrointestinal stromal tumours.
AIM: To study the clinical features, histology and immunohistochemical properties of gastrointestinal stromal tumours (GISTs); and establish any parameters that can help prognosticate the malignant potential. METHODS: Twenty-six patients with GISTs who were seen in Sultanah Aminah Hospital Johor, Malaysia from 1999 to 2003 were selected for study. Patient, clinical characteristics and outcome based on surgical records were analysed. Tumour variables (tumour size, cellularity, mitotic count, necrosis and haemorrhage) were compared between very low to low risk groups and intermediate to high risk groups. The immunohistochemical properties of GISTs were also studied. RESULTS: Patients with GISTs presented mainly with pain, palpable mass or gastrointestinal tract bleeding. The tumours were seen in stomach (50%) followed by small intestine (38.5%) and rectum (11.5%). In the period of study, six patients had metastasis, mainly in the liver or peritoneum. Immunoreactivity for CD117, CD34, vimentin, S100, neuron specific enolase, alpha-smooth-muscle-actin and desmin were observed in 100%, 76.9%, 61.5%, 46.1%, 80.8%, 11.5% and 0% of tumours respectively. The behaviour of GISTs was largely dependent on tumour size and number of mitosis. Necrosis and haemorrhage were seen in tumours with high risk potential.
Scar endometriosis presenting as an acute abdomen: a case report.
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Extramammary Paget's disease: a report of 2 cases and a review of the literature.
Extramammary Paget's disease (EMPD) is a rare disorder and may be found in the vulva, scrotum, penile area, perianal region and the groin. Frequently, it is associated with an underlying regional neoplasm or internal malignancy. We report 2 cases of EMPD; one involving the scrotal area and the other the vulva. Both were elderly patients who presented to the dermatologists with chronic eczematous lesions in the perineum that did not respond to topical treatment. Skin biopsies confirmed extramammary Paget's disease. Investigations for internal malignancies were negative. However, one of the patients defaulted treatment before surgery. The other patient had two excision surgeries with skin grafting to try to achieve tumour free margins. A long term follow-up was planned for him to look for recurrences. These cases emphasise that EMPD can mimic exudative dermatitis and present as a chronic non-healing lesion in the perineum for many years. Clinicians should have a high index of suspicion to pick up the disease early by biopsy. Various immunohistochemical markers not only can help differentiate other histological diagnoses but also help predict the presence of underlying malignancies. Management of EMPD included thorough search for occult or underlying malignancy followed by complete excision surgery with intraoperative frozen sections. Even then, recurrences are high for this disease and long term follow-up is advocated.