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Biomedical subjects

C S Sim

Publications and source records attributed to C S Sim.

At least 19 recordsLinked to original sources

Assessment of blood-induced cartilage damage in rabbit knees using scanning electron microscopy.

PURPOSE: To investigate the harmful effects of a single episode of intra-articular bleeding on articular cartilage of rabbit knees using scanning electron microscopy. METHODS: Autologous blood was injected into the right knee joints of 18 New Zealand white rabbits. Surface and cellular damages were examined by the scanning electron microscope (n=9) and light microscope (n=34), respectively. The injected right knees were then compared with the corresponding control left knees at one, 3, and 6 weeks after the blood injection. RESULTS: The articular surface of the injected knees turned uniformly rough with multiple pits after one week. Maximal changes with elevations and depressions were observed at 3 weeks. These changes reversed at 6 weeks with the irregularities smoothing out. A similar pattern of transient cartilage damage was noted histologically. CONCLUSION: Both scanning electron microscopic and light microscopic findings suggest that a single episode of intra-articular bleeding leads to articular cartilage damage but this appears to be reversible. Our findings of transient damage to the articular cartilage suggest that there is no need for intra-articular evacuation and washout following an acute episode of haemarthrosis.

Animals↗

Two case reports of metastases from colon carcinoma to the thyroid.

INTRODUCTION: Secondary malignancy of the thyroid gland is uncommon, but it is a problem requiring ongoing recognition. As it is more common than primary thyroid malignancy, metastatic disease involving the thyroid gland should be actively excluded in a patient with enlarging or abnormal thyroid gland and a previously known primary tumour. CLINICAL PICTURE: We report 2 cases of primary colon carcinoma with metastasis to the thyroid gland that mimicked thyroid anaplastic carcinoma. In both cases, airway compromise was evident. TREATMENT AND OUTCOME: Emergency tracheostomy was necessary in the first case with subsequent oxaliplatin-based chemotherapy providing palliation of symptom of breathlessness, with significant reduction in size of thyroidal metastasis. Palliative thyroidectomy relieved airway compromise in the second case. CONCLUSION: Our case report highlights the importance of early recognition of thyroidal metastases from a colonic primary as life-threatening airway compromise may otherwise rapidly ensue.

Adenocarcinoma↗

Cutaneous lymphomas other than mycosis fungoides in Singapore: a clinicopathological analysis using recent classification systems.

BACKGROUND: Cutaneous lymphomas other than mycosis fungoides (MF) are a heterogeneous group with wide variations in clinical presentation, biological behaviour and prognosis. New classification systems have been designed or proposed in recent years, with well-defined disease entities and emphasis on the importance of site. OBJECTIVES: This study aims to analyse a series of non-MF lymphomas in an institution-based dermatological setting in Singapore, based on the European Organization for Research and Treatment of Cancer (EORTC) classification and the World Health Organization (WHO) classification. A secondary objective is to highlight the clinical utility of both classification systems. PATIENTS AND METHODS: Forty cases diagnosed over a 12-year period were examined by immunohistochemistry with antibodies targeting CD3, CD4, CD5, CD8, CD20, CD30, CD43, CD45RO, CD56 and CD68 in paraffin-embedded specimens. The immunohistological diagnosis was correlated with the clinical presentation and staging investigations for the final diagnosis and the course of disease recorded. RESULTS: Non-MF T-cell lymphomas presenting in the skin comprised 31 cases (78%) and were 3(1/2) times more common than B-cell lymphomas, which comprised nine cases (22%). The common subtypes were lymphomatoid papulosis, CD30+ large cell cutaneous T-cell lymphoma and subcutaneous panniculitis-like T-cell lymphoma. The commonly ascribed B-cell pattern with infiltrates in the mid and deep dermis and perivascular spaces was seen in 60% of T-cell lymphomas. Overall, there were equal numbers of primary cutaneous T-cell lymphomas and those due to concurrent or secondary cutaneous lymphoma. Five of six cases of subcutaneous panniculitis-like T-cell lymphoma had concurrent cutaneous and systemic involvement and their median survival was 7 months. CONCLUSIONS: The predominance of cutaneous T-cell lymphomas in this case series closely matched that reported from east Asia; cutaneous B-cell lymphomas are much less common than in Europe. The EORTC classification, which is designed only for primary cutaneous lymphomas, should be used in conjunction with the WHO classification because of the high prevalence of cutaneous lymphomas as the secondary site of disease from systemic lymphoma. In addition, subcutaneous panniculitis-like T-cell lymphoma is a primary cutaneous lymphoma where systemic involvement is common at initial presentation. We propose full immunophenotyping and complete clinical evaluation with staging investigations for all patients presenting with cutaneous lymphomas other than MF.

Adolescent↗

A case of Bizarre Parosteal Osteochondromatous Proliferation of the hand.

We report a case of Bizarre Parosteal Osteochondromatous Proliferation (BPOP) of the hand that was initially misdiagnosed as an osteochondroma. BPOP, although a benign lesion, behaves aggressively with rapid growth and high risk of local recurrence after local resection. The distinguishing features of BPOP as opposed to an osteochondroma are discussed.

Adult↗

A retrospective study of melanocytic naevi at the National Skin Centre.

INTRODUCTION: A retrospective study of melanocytic naevi was undertaken to assess the degree of clinico-pathological correlation and incidence of histological atypia. MATERIALS AND METHODS: The case records from January to March 1996 of all patients with histologically diagnosed melanocytic naevi at the National Skin Centre were analysed. RESULTS: Of the 240 lesions removed from 167 patients, the majority being women (111/167 patients), it was found that 55% (132/240) were correctly diagnosed. Fourteen per cent were mistaken for non-melanocytic lesions, namely skin tag, neurofibroma, syringoma cylindroma, epidermal naevus, naevus sebaceous and basal cell carcinoma. Most of the lesions were located on the cheeks and eyelids. Junctional naevi, followed by compound naevi were often missed. Histological dysplasia were seen in 7 naevi; 6 compound and 1 congenital naevi. There was a lack of clinico-pathological concordance in dysplastic naevi. CONCLUSIONS: The clinico-pathological concordance of melanocytic naevi was high, with low incidence of atypia on histology.

Adolescent↗

Autogenous osteochondral morselised grafts for full thickness osteochondral defects in the knee joints of pigs.

The aim of this study is to firstly ascertain the survival of autogenously grafted morselised cartilage for full thickness osteochondral defects in knee joints of pigs. Secondly, it is to determine the quality of the grafted cartilage that survives and to score to it based on a recognised and tested system of indices and thirdly, to recognise, if any, the potential for reconstitution of the osteochondral junction. Two groups of five pigs were followed up for six and 12 weeks. Similar osteochondral defects were created in the medial condyles of both knees with the right medial femoral condyle defect filled with graft and the left used as control and filled with gel foam. At the end of the study period, an independent pathologist assessed the defects macroscopically and microscopically with an accepted and comparable histological scoring system. Macroscopically, there was better filling of the defect and restoration of bony contour in the grafted group compared to the control. Microscopically, at six weeks, filling of the defect, nature of predominant tissue, matrix staining and nature of cells all showed significantly better histological score than the control using the Mann-Whitney U test at the level of significance of p<0.05. At 12 weeks, in addition to the above, the reconstitution of osteochondral junction also showed a significantly better score. Comparing the test groups at six and 12 weeks, the reconstitution of the osteochondral junction was significantly better at 12 weeks. In conclusion, the autogenous osteochondral morselised graft persisted as mature hyaline cartilage with good histological score at six weeks with significantly better reconstitution of osteochondral junction occurring at 12 weeks. The use of morselised graft allows for the inclusion of bone graft which possibly allows for larger amounts of donor tissue and thus the possibility of treating larger defects. In the human model the donor site would be the non-weight bearing surfaces of the knee such as the intercondylar notch as described by Walgenbach A and Stone KR at the 1997 Annual Meeting of the American Academy of Orthopaedic Surgeons in San Francisco.

Animals↗

Non-steroidal anti-inflammatory drugs, Helicobacter pylori and bleeding gastric ulcer.

BACKGROUND: Helicobacter pylori infection and NSAID usage are considered to be independent risk factors for gastric ulcer (GU). Whether they interact to influence the risk of bleeding in GU is unclear. AIM: To determine the prevalence of H. pylori infection and NSAID ingestion in a group of patients with GU and determine their roles in bleeding and non-bleeding GU. METHODS AND RESULTS: From January 1993 to June 1996, a total of 217 GU patients (150 male, 67 female, median age 61 years, range 26-94) were eligible for the study. Eighty-five per cent were H. pylori-positive and 15% were H. pylori-negative. NSAID usage within 4 weeks prior to endoscopy was present in 30%, more in the H. pylori-negative than H. pylori-positive patients (59% vs. 25% P = 0.0002). Aspirin was most commonly used (43%). One hundred patients bled from GU (69 male, 31 female, mean age 67 years, range 26-94) and 117 did not (81 male, 36 female, mean age 57 years, range 28-86). Univariate logistic regression showed that advanced age (>/= 65 years) and NSAID usage carried an increased risk of bleeding GU (odds ratio 3.4 and 6.8, respectively) while H. pylori infection alone was not associated with additional risk (OR = 0.8). However, when three variables were considered jointly in a multiple logistic regression, the OR associated with H. pylori infection increased to 2.4, suggesting that in the presence of NSAIDs and advanced age, H. pylori also increases the risk of bleeding GU, indicating an interaction between the variables. CONCLUSION: NSAID usage and advanced age are risk factors for bleeding GU, whereas H. pylori infection by itself is not. In the presence of NSAIDs and advanced age, an increased risk of bleeding GU with H. pylori is observed, indicating the possibility of an interaction between these factors.

Adult↗

Metaplastic carcinoma of the breast arising within complex sclerosing lesion: a report of five cases.

AIMS: This study presents a series of five cases in which metaplastic carcinoma, predominantly low-grade adenosquamous carcinoma, of the breast is seen arising within a background of a complex sclerosing lesion. This association has been recognized previously but has not been documented in detail. This study describes the characteristics of the components present in each case and discusses the existing literature. This observation adds further evidence to support an association between some types of invasive breast carcinoma and sclerosing lesions of the breast. METHODS AND RESULTS: Four of these cases were received as referral cases for opinion. The fifth was received as part of the routine surgical workload within our own institution. Two patients presented following mammographic screening and three symptomatically; their mean age was 62 years (range 49-68). The mean lesion size was 16 mm (range 7-24). All five lesions showed features of a complex sclerosing lesion/radial scar in the form of central sclerosis with elastosis and radiating benign entrapped tubules. One had associated benign papillary structures and two had focal benign squamous metaplasia. Four cases showed coexisting but distinct areas of low-grade adenosquamous carcinoma with glandular and squamous epithelial differentiation in a spindle cell background. One case had associated undifferentiated spindle cell carcinoma. Detailed immunophenotypic characteristics of two cases are presented. CONCLUSIONS: This series illustrates a postulated but previously unconfirmed association between an unusual form of metaplastic breast carcinoma (adenosquamous carcinoma) and complex sclerosing lesions. The mechanisms of induction of breast carcinoma are poorly understood but these observations further emphasize the potential for sclerosing lesion of the breast to be associated with, and possibly give rise to, invasive carcinoma of different types. The precise nature of the interaction between the pathological processes remains unclear.

Aged↗

Recurrence of Helicobacter pylori infection and duodenal ulcer relapse, following successful eradication in an urban east Asian population.

We aimed to determine the rate of Helicobacter pylori (HP) recurrence and duodenal ulcer relapse in patients of a hospital in Singapore over a period of at least one year from the time of eradication. Ninety-six consecutive duodenal ulcer patients with biopsy-proven HP eradication and healed ulcer were seen at 3-month intervals, and follow-up endoscopy was performed when dyspepsia recurred, at the end of one year after eradication, or at the time of recall if the patient had been lost to follow-up. HP status was determined by antral and corpus biopsies and by antral cultures. Sixty-five had been given triple therapy, and 31 received dual therapy with omeprazole + amoxycillin or clarythromycin. Median time to follow-up endoscopy was 12 months. Six patients (6.25%) were positive for HP infection after eradication. Recurrence of HP infection was detected at 9 and 10 months after confirmation of HP eradication in two patients, and at between 13 and 20 months in the remaining four. Two of these had recurrent duodenal ulcer; all but one had erosive duodenitis. Two other patients had recurrent duodenal ulcer despite absence of HP reinfection; they admitted to taking low-dose aspirin. It was concluded that the recurrence of HP infection is low at the end of one year after successful eradication therapy in this urban East Asian population. Ulcer relapse occurred in 4.17% (4/96) of patients, and was associated with recurrent HP infection or NSAID exposure.

Adolescent↗

The results of autogenous tibial periosteal transplants for full thickness cartilage defects in the knee joints of pigs.

An experimental study was conducted to demonstrate macroscopic and microscopic healing of full thickness cartilage defects with mature stable hyaline cartilage after autogenous tibial periosteal transplants in the knee joints of pigs. Similar full thickness osteochondral defects were created in the medial femoral condyles of both knees in 10 healthy young adult pigs. Periosteal transplants were performed on the left knees and the right knees used as controls. The pigs were sacrified in two groups at 6 weeks and 3 months. The knees were inspected for healing and stability of the graft. Microscopic sections were taken and evaluated using a histological score developed by O'Driscoll. Macroscopically, almost all defects with periosteal grafts healed with a translucent bluish-white colour indicating articular cartilage formation. There was good restoration of the bony contour and filling of the defects were superior to controls. Histologically, we were able to demonstrate immature hyaline cartilage which matured at 3 months. The newly formed tissue was stable and well-incorporated. It had almost complete bonding to the adjacent articular margin, good reconstitution of the osteochondral junction and a well maintained structural integrity. We concluded that periosteal transplants in the knee of a pig model healed with mature stable hyaline cartilage.

Animals↗

Cryptococcal prostatic abscess in an immunocompromised patient: a case report and review of the literature.

A case of cryptococcal prostatic abscess in a 65-year-old Chinese man with immunosuppression from treatment of myasthenia gravis is presented. The patient was diagnosed to have cryptococcaemia when he presented with fever and urinary symptoms. Further investigations confirmed cryptococcal meningitis and imaging studies showed a hypodense lesion in the prostate. This proved to be an abscess and it was deroofed transurethrally. Histology of the prostatic tissue revealed the presence of Cryptococcus. The prostate can be a site of persistent cryptococcal infection and may take the form of an abscess. It should be drained transurethrally to prevent relapse.

Abscess↗

Helicobacter pylori infection and gastric emptying of indigestible solids in patients with dysmotility-like dyspepsia.

BACKGROUND: The role of Helicobacter pylori and gastric motility in dysmotility-like dyspepsia is unclear. The aim of this study was to determine whether delayed gastric emptying of indigestible solids and H. pylori infection are associated with dysmotility-like dyspepsia. METHODS: Thirty-two healthy volunteers and 72 patients fulfilling the criteria of dysmotility-like dyspepsia received a gastric emptying test using radiopaque markers, and the H. pylori status was determined by histology. RESULTS: Twenty-seven percent of volunteers were H. pylori-positive, compared with 32% in the dyspeptic groups (P = NS). Gastric emptying was significantly slower in dyspeptic patients than controls and in H. pylori-positive patients than H. pylori-negative patients. Subjects with gastroparesis have a higher chance of developing dysmotility-like dyspepsia (odds ratio (OR), 2.5) than subjects with normal gastric emptying. Subjects with H. pylori and gastroparesis have an increased likelihood of developing dysmotility-like dyspepsia (OR, 4.3) than if either factor were present alone. CONCLUSION: Our data suggest that gastroparesis alone and gastroparesis and H. pylori infection are associated with dysmotility-like dyspepsia.

Adult↗

Paraganglioma with pulmonary metastases: a case report.

Distant metastases due to paraganglioma are a rare occurrence. We report a case of paraganglioma with pulmonary metastases and review the literature on paragangliomas. A 29-year-old female presented with cervical lymphadenopathy, excision biopsy of which confirmed the diagnosis of paraganglioma. She subsequently underwent tumour embolisation and received a course of radiotherapy. Seven years later, she was investigated for multiple pulmonary nodules noted on her chest roentgenogram. Histology of the wedge excision of the lung showed metastatic paraganglioma. Increased catecholamine production was documented; this was however not associated with symptoms of catecholamine excess. Reports concerning the treatment of paragangliomas with pulmonary metastases are few, given their rarity.

Adult↗

Systemic lupus erythematosus with erythema multiforme-like lesions and histiocytic necrotizing lymphadenitis--a case report.

A 9-year-old Chinese girl with systemic lupus erythematosus presented initially with persistent cervical lymphadenopathy without any constitutional symptoms. The histology of the involved lymph node showed histiocytic necrotizing lymphadenitis and the initial clinical diagnosis of Kikuchi-Fujimoto disease was made. The patient subsequently developed fever, oral ulcerations, epistaxis, generalised myalgia and erythema multiforme-like skin lesions over the face and upper arms. Investigations showed anaemia, leucopenia, hypocomplementemia, a positive antinuclear antibody and a positive anti-double-stranded DNA antibody test. The clinical diagnosis was revised to systemic lupus erythematosus. The histological picture of histiocytic necrotizing lymphadenitis can occur in systemic lupus erythematosus and may be indistinguishable from that seen in Kikuchi-Fujimoto disease. The diagnosis of Kikuchi-Fujimoto disease should be confined to a benign clinical subset of histiocytic necrotizing lymphadenitis which resolves spontaneously without treatment. The occurrence of erythema multiforme-like lesions in lupus erythematosus is unusual and together with the characteristic serologic abnormalities, fits Rowell's syndrome.

Child↗

Nodular skin tuberculosis with lymphatic spread--a case report.

An unusual case of tuberculosis paronychia with skin infection of the big toe was recently seen in a patient returning from Kalimantan. This was complicated by inguinal lymphadenitis and tuberculosis abscess formation. The diagnosis was made on culture of the pus from the abscess and upon biopsy and histological examination of the skin lesion from the toe. The patient responded to surgical treatment and chemotherapy with ethambutol, rifampicin and isoniazid.

Adult↗

Gastric ulceration with acute bleeding from tuberculosis of the stomach--a case report.

Tuberculosis of the stomach is a rarity. Its diagnosis is difficult as it is often unsuspected or unrecognised. This is a case report of an elderly man who presented with active upper gastrointestinal tract bleeding. The diagnosis was made postoperatively following gastrectomy for bleeding gastric ulcers. The histological specimens showed caseating epithelioid granulomas with Langerhan's giant cells centrally. The authors reviewed the recent literature on tuberculosis of the stomach, and suggest ways to identify the patients at risk.

Aged↗