Biomedical subjects
Publications and source records attributed to C S Sim.
Alveolar soft part sarcoma of the tongue is a rare malignancy. Until 1988, only 23 cases have been documented in the English literature. In this report, a 21 year old man with typical features of alveolar soft part sarcoma of the tongue is presented. Treatment was wide surgical resection with reconstruction using a pectoralis major myocutaneous flap.
A total of 26 specimens of histologically determined, cutaneous Bowen's disease from 23 patients were investigated for the incidence of mutant p53 protein expression by an indirect immunoperoxidase technique using the monoclonal antiserum CM1 on paraffin-embedded formalin-fixed tissue sections. Its potential role as a label of cutaneous malignancy was also evaluated: 15 specimens (57.7%) showed nuclear positivity of dysplastic keratinocytes, whereas 11 specimens (42.3%) were immunonegative. Cytoplasmic labeling was never a feature. In general, labeling was predominantly diffuse in distribution although in a significant proportion it was focal. One of two concurrent basal cell carcinomas arising adjacent to plaques of Bowen's disease was immunopositive. Focal immunopositivity of "cytologically normal" adjacent epithelium was seen in six specimens (23%). The study confirms the presence of mutant p53 protein in the majority of nongenital Bowen's disease. Its identification within nuclei of the adjacent "normal" epidermis may represent a potential marker of early (visible) neoplastic transformation.
Of 128 cases of malignant lymphomas studied in Singapore between 1986 and 1988, 28 were identified as peripheral T-cell lymphomas. Sera from two of the 128 cases were positive for HTLV-1 antibodies and both cases had the clinical and pathological features of adult T-cell leukaemia/lymphoma. The pathological and clinical features of the 28 cases of peripheral T-cell lymphoma are presented in detail. Survival data indicated no significant difference between the low grade and high grade histological types. Three of the patients had previous or concomitant malignancies. The percentage of T-cell lymphomas associated with HTLV-1 infection in Singapore is low compared to those areas in which HTLV-1 is endemic.
Thirty-eight solar keratoses from 32 patients were studied for expression of mutant p53 protein by an immunohistochemical technique. Twenty-eight of the 38 solar keratoses (73.7%) showed positive and variable nuclear labelling, whereas 10 specimens were immunonegative. The nuclear immunopositivity which was seen in all variants was mostly diffuse in distribution. The adjacent "normal" epidermis of 8 keratoses showed positive mutant p53 labelling. Eight of the keratoses were associated with invasive squamous cell carcinoma of which only two were immunopositive. Cytoplasmic labelling was never a feature. The study demonstrates that mutant p53 protein is commonly expressed in all variants of solar keratosis and that its expression correlates with atypical keratinocyte proliferation. It is proposed that the demonstration of mutant p53 in the adjacent normal epidermis may be a potential marker of early neoplastic transformation.
An unusual case of massive bleeding per rectum caused by erosion into the caecum of placental tissue from an ectopic pregnancy is presented. Despite its rarity, abdominal pregnancies may have to be considered in sexually active fertile women presenting with difficult torrential bleeding from the lower gastrointestinal tract.
Tuberculosis is a common cause of cavitating pneumonia in Singapore. In patients with the human immunodeficiency virus (HIV), cavitary pneumonias mimicking tuberculosis can mislead the clinician, delaying diagnosis, resulting in increased morbidity. We describe a HIV seropositive patient with cavitating pneumonia in whom the diagnosis of Pneumocystis carinii pneumonia (PCP) was ultimately established only on bronchoscopy.
Calcifying epithelioma of Malherbe (pilomatrixoma) is a relatively uncommon benign skin tumour of hair follicle origin. It usually presents in the face and upper extremities of young adults as an asymptomatic subcutaneous or dermal tumour. Treatment is surgical excision. This paper presents a case of a large tumour in the preauricular region with difficulty in diagnosis preoperatively and required a superficial parotidectomy to clear the tumour from the facial nerve.
Actinomyces species are rare but treatable causes of central nervous system infection. A case of actinomycotic cerebral abscess is reported. The primary source of infection was probably the lung based on radiological findings although culture of the bronchial brushings was negative. The patient had surgical excision and repeated drainage with two prolonged causes of antibiotic therapy. At follow-up examination 36 months later, the patient was well except for a residual left hemiplegia. Diagnosis of cerebral actinomycosis can be made by anaerobic culture of the appropriate specimens or on histologic grounds. Optimal management combines adequate surgical drainage and prolonged antibiotic therapy.
Chondrosarcoma arising from the spine is a rare malignant tumour, associated with a poor outlook due to inadequate excision in the majority of the cases. We report two cases arising from the cervical and the thoracic spine. Both survived 15 and eight years respectively. This condition carries with it a grave prognosis because of its proximity to the vital structures, making complete extirpation of the tumour frequently difficult if not impossible. Recent developments and progress in adjuvant radiation therapy has improved the prognosis significantly.
Adrenal cysts are a rare entity. Only about 300 cases have been reported throughout the world. A case of an asymptomatic, benign, non-functioning adrenal cyst of the left adrenal gland is presented. Pre-operative diagnosis is usually by incidental imaging findings as the majority of adrenal cysts are asymptomatic. The adrenal cyst in this case was detected on an abdominal ultrasound for the investigation of jaundice, and confirmed by a CT scan examination. Selective biochemical studies are needed to assess adrenal function, and here they were normal. Simple surgical enucleation of the cyst, with preservation of remaining adrenal tissue is the treatment of choice.
Adenocarcinoma in association with chronic anal fistula is a rare disease entity with a male preponderence in most reported series. The patient typically presents with a long history of perianal disease. Diagnosis is often delayed because of failure to obtain biopsy evidence of the condition. A chronic anal fistula may become malignant. However, despite delay in diagnosis, complete removal which usually entails abdominoperineal resections with wide excision of perianal skin and ischiorectal fossa is necessary to achieve good results. We relate our experience with two such rare cases and a literature review on the current views on the relationship between adenocarcinoma and the occurrence of anal fistula is presented.
The sue of bone wax is commonly used to control bleeding during mastoid surgery. An unusual case of bone wax granuloma in the mastoid, with sigmoid sinus thrombosis, is reported. Although the use of bone wax in and around the mastoid is generally considered safe with few complications, caution should be exercised, particularly in infected fields and in patients known to have general immunohypersensitivity.