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C Choy

Publications and source records attributed to C Choy.

32 records · Page 2Linked to original sources
PubMed1999

Desmoplastic malignant melanoma on the buttock of an 18-year-old girl: differentiation from desmoplastic nevus.

Melanocytic proliferation in young people may sometimes pose a diagnostic dilemma. This is particularly so when a desmoplastic component is present. Because the two main differential diagnoses, desmoplastic malignant melanoma and desmoplastic Spitz nevus, share some morphologic features, the diagnosis of desmoplastic malignant melanoma may be overlooked. Distinction between the two is important because they show completely different biological behavior. The age of patient, site of lesion, histologic findings of melanocytic atypia, neurotropism, mitosis, and maturation help to distinguish the two entities. We report a case of desmoplastic malignant melanoma occurring in the buttock of an 18-year-old Chinese girl. Histologically, it had typical features of desmoplastic malignant melanoma with junctional melanocytic atypia and prominent neurotropism. Clinical and histologic differences between desmoplastic malignant melanoma and desmoplastic Spitz nevus are reviewed. We conclude that although desmoplastic Spitz nevus occurs much more commonly in adolescents, desmoplastic malignant melanoma can occur in this age group and even in non-sunexposed skin. Microscopic findings remain the mainstay that guides the final diagnosis.

Adult↗
PubMed1999

Isolated uterine relapse of nasal T/Nk cell lymphoma.

A case of isolated uterine relapse of nasal T/NK cell lymphoma is reported. A 47-year old lady developed menstrual symptoms a year after attaining complete remission from her nasal T/NK cell lymphoma. Endometrial tissue showed characteristic zonal necrosis, angiocentricity and infiltration by lymphoma cells that were positive for both the characteristic immunopheotypic profile of T/NK cell (CD2+, surface CD3-, cytoplasmic CD3 [CD3epsilon]+ and CD56+) and EBER.

Antigens, CD↗
PubMed1991

Neutrophils in chronic active hepatitis type B.

Liver biopsy specimens from 95 patients with chronic active hepatitis type B were studied to define the incidence of portal tract and/or septal neutrophilic infiltration and its relationship with other morphohistologic factors and with liver function tests. Neutrophils were identified in the portal tracts and fibrous septa in 59 cases (62%), among which 19 cases (20%) showed four or more neutrophils per high-power field. Significant neutrophilic infiltration (greater than 6 per high-power field) was observed in only seven (7.4%) of 95 cases. Multiple-regression analysis revealed that neutrophilic infiltration was significantly associated with marginal duct proliferation, bile duct proliferation, and an elevated alanine aminotransferase level. Applying a partial correlation coefficient, it was shown that neutrophilic infiltration was not related to piecemeal necrosis after controlling for marginal duct proliferation or bile duct proliferation. The findings suggest that in chronic active hepatitis B, while piecemeal necrosis interferes with bile flow at the limiting plate region, marginal duct and bile duct proliferations follow and lead to the accumulation of neutrophils.

Adolescent↗
PubMed1982

Pathology of motor neurons in accelerated hereditary canine spinal muscular atrophy.

Hereditary canine spinal muscular atrophy is a dominantly inherited lower motor neuron disease with three phenotypic variants: accelerated, intermediate, and chronic. Pups with the accelerated disease develop weakness by 1.5 months and are quadriparetic by 3 months. The motor neurons of selected brainstem nuclei and ventral horn of the spinal cord are characterized by chromatolysis and by neurofibrillary abnormalities in perikarya, dendrites, and, most strikingly, proximal axons. Dendrites and axons are segmentally enlarged by accumulations of maloriented fascicles of neurofilaments; the axonal swelling usually involve internodes and are delimited by the initial segment or nodes of Ranvier. The disorganized neurofilaments appear to entrap mitochondria and other particular organelles. We have hypothesized that the neurofibrillary changes in this genetic disorder in dogs is associated with an abnormality of the cytoskeletal constituents of motor neurons. Hereditary canine spinal muscular atrophy shows features in common with human motor neuron disease.

Animals↗
PubMed1980

Diffuse cystitis glandularis. Associated with adenocarcinomatous change.

Although cystitis glandularis has been considered a premalignant lesion, the instance of cystitis glandularis progression to adenocarcinoma or cystitis glandularis associated with adenocarcinomatous change is rare. This article includes 4 cases of neurogenic bladder with urinary diversion for different periods of time. In the first case with ureterocutaneostomy for twenty-five years diffuse cystitis glandularis with multifocal adneocarcinomatous change developed. The second case with suprapubic cystostomy for twenty-two years had diffuse cystitis glandularis of gastrointestinal type without evidence of malignancy. The other 2 cases with suprapubic cystostomy for merely ten years showed only mild to moderate cystitis glandularis and chronic cystitis with squamous metaplasia, respectively. The extent of cystitis glandularis appeared to correlate with the duration of urinary stasis. Ureterocutaneostomy rendered constant infection of the urinary bladder of the first case because of inadequate drainage. Thus, we assume that the intensity of the infection with a toxic product and virulence of organism may be responsible for the development of adenocarcinoma in this patient. Cystitis glandularis, especially diffuse type, can undergo malignant degeneration under constant irritation, but it is a long-term process.

Adenocarcinoma↗
PubMedDate not supplied

Fine needle aspiration cytology of epithelial-myoepithelial carcinoma of salivary glands. A report of three cases.

BACKGROUND: Epithelial-myoepithelial carcinoma is a rare, low grade malignant tumor of the salivary glands. Histologically, it has a biphasic cellular composition and exhibits a high degree of differentiation. The fine needle aspiration cytology of this rare tumor is rarely described in the literature. CASES: We report the fine needle aspiration cytology of three epithelial-myoepithelial carcinomas, arising in the right parotid, left parotid and minor salivary gland of the hard palate. Cytology showed a biphasic population consisting of cells of ductal epithelial and myoepithelial origin arranged in small clusters and sheets. The myoepithelial cells had small, uniform nuclei; ample, clear cytoplasm and distinct cell borders, while the ductal epithelial cells had larger, mildly pleomorphic nuclei and scanty cytoplasm. These ductal cells tended to form tubules among background sheets of clear myoepithelial cells. This feature, if present, was an important diagnostic clue. Hyaline material surrounding cell clusters and focal adenoid cystic carcinoma-like areas with orangeophilic globules were also not uncommon. CONCLUSION: While the cytologic appearance of epithelial-myoepithelial carcinoma may closely mimic that of other salivary gland tumors, such as adenoid cystic carcinoma, pleomorphic adenoma and basal cell adenoma, certain peculiar cytologic features may allow a distinction to be made on fine needle aspiration biopsy.

Aged↗