Pattern of hMLH1, hMSH2 and hMSH6 expression and clinical characteristics in a sample of Malaysian colorectal carcinoma cases

Malignant transformation from normal colonic mucosa to carcinomas may be accelerated by genetic loss or inactivation of genes of the DNA mismatch repair system. The aim of the study was to determine the local incidence and pattern of immunohistochemical expression of mismatch repair proteins namely: hMLH1, hMSH2 and hMSH6 in a series of colorectal carcinomas (CRCs) and correlate this to their clinical and pathological features. Forty-three out of 298 cases of CRCs (14.4%) showed abnormal staining pattern for mismatch repair proteins with a majority (65.1%) showing single hMLH1 loss. Tumours with mismatch repair defect (MMR-d) were frequently found at the right side of colon (p<0.001), poorly differentiated carcinomas (p<0.001), produced more mucin (p=0.007), exophytic growth (p=0.007) and were bigger (p=0.002) than tumours with no mismatch repair defect. Immunohistochemical stains for mismatch repair proteins could be done in local laboratories on these selected cases before referring for the expensive molecular test.

Myoid hamartoma of breast with chondroid metaplasia: a case report

Breast hamartoma is an uncommon poorly recognised benign breast neoplasm. Hamartoma displaying marked smooth muscle components known as myoid hamartoma of the breast is a much rarer entity. We present a case of myoid hamartoma of breast with chondroid differentiation in a 46-year-old woman. The painless breast lump was circumscribed and mammography showed a well-encapsulated large, dense mass with no calcification. Core needle biopsy was reported as fibroadenoma. The lesion was excised. Microscopically, it composed of many groups of mammary glandular components with dense fibrous stroma, adipose tissue and marked groups of smooth muscle fibres. Foci of chondroid differentiation were noted in the lesion. The smooth muscle cells showed strong and diffuse immunoreactivity for vimentin, myogloblin, alpha-smooth muscle actin, desmin and CD34 and failed to express pan-cytokeratin or S100 protein. The ducts lined by epithelial cells were reactive to pan-cytokeratin while the myoepithelial cells were reactive to S100 protein. The various immuno-histochemical staining as well as the cyto-histological changes encountered in myoid hamartomas are discussed with clinical, radiological and pathological correlation to differentiate it from other benign and malignant breast lesions.

A clinicopathological study of nine cases of gallbladder carcinoma in 1122 cholecystectomies in Johor, Malaysia

An audit of 1122 cholecystectomies for a 6-year period from 2000 to 2005 was done to review cases of primary carcinoma of gallbladder. There were nine cases of primary carcinoma of gallbladder. Six were females and 3 males. Their ages ranged from 27 to 81 years. Pre-operatively, only 2 (11.1%) were clinically suspected of carcinoma while 3 were diagnosed as cholecystitis, two as cholelithiasis and one case each of ovarian cyst and intestinal obstruction. Intra-operatively, an additional four cases were suspected as gallbladder carcinoma with the remaining three cases diagnosed as only having gallstones. Altogether only 5 (55.6%) cases were associated with gallstones. Six (66.67%) cases of gallbladder carcinoma had abnormal macroscopical lesions noted; either papillary lesions or polypoid masses. The remaining 3 cases had thickening of the wall, consistent with chronic cholecystitis. Seven cases were found histologically to be adenocarcinoma. Of these, two were papillary carcinoma and one signet ring cell type adenocarcinoma. One case of squamous cell carcinoma and one case of adenosquamous carcinoma were noted. This study highlights the importance of careful macroscopical and microscopical evaluation of a routine pathological examination of gallbladder removed for cholecystitis or cholelithiasis. It provides the incidence of gallbladder carcinoma in patients who underwent cholecystectomies in a government hospital in Johor, Malaysia.

Cutaneous Rosai-Dorfman disease

Rosai-Dorfman disease (RDD) is a rare benign proliferative disorder of histiocytes in the lymph nodes with or without extranodal involvement. RDD limited to the skin without nodal involvement, known as cutaneous Rosai-Dorfman disease, is very rare. We describe a 34-year-old female with RDD of the skin over the chest. A large nodule with satellite lesions was excised for histopathological examination. Microscopically, there were many large histiocytes (Rosai-Dorfman cells) exhibiting emperipolesis, among many plasma cells, lymphocytes and neutrophils throughout the dermis and the subcutaneous tissue. The histiocytes were immunohistochemically positive for S-100 protein but negative for CD 1a. Physical examination showed no lymphadenopathy or any extra-cutaneous lesions. Serological tests indicated a past infection with Epstein-Barr virus and cytomegalovirus. The diagnosis of cutaneous RDD may be difficult in the absence of associated lymphadenopathy or any specific features of the skin lesion. Hence, not only is histopathological examination required for definitive diagnosis but a high index of suspicion by the clinicians and pathologists is essential to help diagnose this very rare disease.

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.

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.