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Biomedical subjects

J K Chan

Publications and source records attributed to J K Chan.

At least 199 records · Page 11Linked to original sources
PubMed1993

Lymphangiomyomatosis and angiomyolipoma: closely related entities characterized by hamartomatous proliferation of HMB-45-positive smooth muscle.

Angiomyolipoma is a hamartomatous condition which can occur as a component of the tuberous sclerosis complex. Lymphangiomyomatosis, another hamartomatous lesion occurring predominantly in the lungs, has long been suspected to be related to angiomyolipoma and tuberous sclerosis because of occasional clinical associations. We undertook this study to provide further support for the close relationship between these two entities. Five cases of lymphangiomyomatosis and 20 case of angiomyolipoma were retrieved for histological review and immunohistochemical studies. The antibodies used were anti-muscle specific actin (HHF-35), anti-desmin (D33) and anti-melanoma (HMB-45). Lesions featuring smooth muscle proliferation were used as controls. The proliferated smooth muscle cells in both lymphangiomyomatosis and angiomyolipoma were much plumper and paler or even clear, when compared with the deeply eosinophilic cytoplasm of the normal spindly smooth muscle cells and those of leiomyomas. Their nuclei were round to oval and pale rather than elongated and dark. Cells with bizarre nuclei were commoner in angiomyolipoma (18/20 cases) than lymphangiomyomatosis (1/5). In 12 cases of angiomyolipoma there were foci indistinguishable from lymphangiomyomatosis, i.e. plump spindle cells arranged in short fascicles around ramifying endothelium-lined spaces. All five cases of lymphangiomyomatosis stained for muscle-specific actin, desmin and HMB-45. For angiomyolipomas, the positivity rates for these markers were: 20/20, 17/20 and 18/20, respectively, including one case that was negative for both desmin and HMB-45. The various smooth muscle proliferations and tumours selected as controls were uniformly HMB-45 negative. The distinctive cytological features, morphological overlap and immunophenotypic profile all support a close relationship between lymphangiomyomatosis and angiomyolipoma, which probably represent different morphological manifestations of hamartomatous proliferation of a peculiar form of HMB-45-positive smooth muscle.

Adult↗
PubMed1993

Mallory's bodies in placental site nodule.

We report two cases of placental site nodule in which Mallory's bodies were found in the intermediate trophoblasts constituting the lesion. Mallory's bodies are known to occur in hepatocytes and pulmonary alveolar cells in a wide variety of conditions, and represent abnormal cytoplasmic aggregates of cytokeratin intermediate filaments. Their occurrence outside the liver and lung is exceptional. In the present cases, they were immunoreactive for both low- and high-molecular-weight cytokeratins. Since high-molecular-weight cytokeratin is not normally expressed in intermediate trophoblasts, the formation of Mallory's bodies appears to involve aberrant expression of cytoskeletal proteins.

Adult↗
PubMed1993

Fine-needle aspiration anchor. A simple device to prevent needle-stick injury at fine-needle aspiration.

Pathologists and clinicians performing fine-needle aspiration for cytologic diagnosis are at risk of finger injury by the needle during the aspiration procedure. To prevent this occurrence and its accompanying potential for transmitting serious pathogens such as the human immunodeficiency virus and hepatitis B virus, we have designed a simple acrylic device (fine-needle aspiration anchor) consisting of two curved prongs with an attached handle, to take up the functions of the fingers for stabilization of the target lesion. Use of the fine-needle aspiration anchor on more than 1000 patients with various mass lesions has confirmed enhanced immobilization of the lesions for aspiration, safety for the person performing the procedure, and excellent patient acceptance.

Biopsy, Needle↗
PubMed1993

Amyloid-producing squamous cell carcinoma of the uterine cervix.

We describe two unusual cases of squamous cell carcinoma of the uterine cervix associated with prominent intratumoral deposition of amyloid. Most of the amyloid is deposited within and between the tumor islands, but some amyloid globules are intracellular. The amyloid shows immunoreactivity for keratin, suggesting that it is derived from cytokeratin intermediate filaments, similar to the pathogenesis of primary cutaneous amyloidosis. Tumor-related amyloidosis is a heterogeneous but distinctive subgroup of amyloidosis, including cytokeratin-derived amyloid deposited within squamous or squamous-related tumors as in the present cases, polypeptide-derived amyloid associated with endocrine tumors, and systemic inflammation-associated amyloid (AA protein) as observed rarely in Hodgkin's disease and renal cell carcinoma.

Aged↗
PubMed1993

The family of epithelioid vascular tumors.

Vascular tumors characterized by proliferation of epithelioid (histiocytoid) endothelial cells with abundant eosinophilic hyaline cytoplasm span a broad spectrum of histologic appearances and behaviour. They can occur in a wide variety of sites, such as soft tissues, skin, bone and visceral organs. On the benign end are the epithelioid hemangiomas (angiolymphoid hyperplasia with eosinophilia), which are composed predominantly of well formed vascular channels, and are frequently accompanied by an infiltrate of lymphocytes and eosinophils. In the literature, they have often been confused with Kimura's disease, an idiopathic allergic-inflammatory condition. There have also been controversies as to whether these lesions are neoplastic or reactive. In the middle of the spectrum are the borderline or low grade malignant epithelioid hemangioendotheliomas, characterized by isolated, cords and nests of epithelioid endothelial cells disposed in a hyaline or myxoid matrix; cytoplasmic vacuoles are common. However, the morphologic variations on this theme are very wide rendering recognition of these tumors difficult sometimes. On the malignant end are highly aggressive epithelioid angiosarcomas showing predominantly solid growth and significant nuclear pleomorphism. In addition, there are also cases showing histologic features straddling the borderline areas between the above three defined categories. In this review, the broad morphologic appearances of these epithelioid vascular tumors are discussed and illustrated.

Animals↗
PubMed1992

Clonal evolution in primary 5q-syndrome.

Primary 5q-syndrome is a type of myelodysplastic syndrome characterized by refractory anemia, thrombocytosis, and hypolobulated megakaryocytes. The risk of leukemic transformation is low. A case of 5q- syndrome that occurred in a 42-year-old woman and was complicated by leukemic transformation 7 years after the initial diagnosis is reported. An additional clonal karyotypic anomaly, del(7q), was seen in the leukemic cells. The literature on leukemic and karyotypic evolution of primary 5q- syndrome is reviewed and the implication of karyotypic evolution is discussed.

Acute Disease↗
PubMed1992

Reactive hemophagocytic syndrome--a clinicopathologic study of 40 patients in an Oriental population.

PURPOSE: The purpose of this investigation was to assess the clinical spectrum and outcome of reactive hemophagocytic syndrome (RHS) in an Oriental population. PATIENTS AND METHODS: The investigation was a retrospective study of 40 consecutive patients with RHS diagnosed over a 4-year period in Queen Elizabeth Hospital, a community-based hospital in Hong Kong. RESULTS: The incidence of RHS in Hong Kong appeared to be comparable with that of Western countries. However, the spectrum of diseases associated with RHS was distinctly different. Forty percent of the cases were associated with malignant lymphoma. Another 40% of the cases were associated with infection, often due to bacteria, and infection due to the herpes group of viruses was uncommon, probably reflecting ethnic and geographic differences from the white population. Two patients had the acute lupus hemophagocytic syndrome, a distinctive form of RHS that occurs in patients with systemic lupus erythematosus. Treatment was basically supportive, with specific therapy also given for the underlying disease if present. Eighteen patients (45%) died of the acute disease, mostly as a result of complications of RHS or the underlying diseases. The development of disseminated intravascular coagulopathy was a poor prognostic factor. CONCLUSIONS: RHS is an uncommon disorder in Hong Kong and is often associated with malignant lymphoma or bacterial infection. A rigorous search for an underlying malignancy or infection is thus warranted once this diagnosis is made.

Adolescent↗
PubMed1992

Pathologic changes of gastric mucosa colonized by Helicobacter pylori.

One hundred eighty-nine consecutive gastric biopsies showing colonization by Helicobacter pylori (HP) were studied. Epigastric pain and bleeding were the clinical presentations in 167 cases (88.4%). Major endoscopic findings were gastritis (n = 72, 38.1%) and ulceration (n = 101, 53.4%). Duodenal ulcer was associated with 32 (44.4%) and 29 (28.7%) cases of gastritis and gastric ulcer, respectively. Histologically, the HP-colonized gastric epithelium showed characteristic degenerative changes that were topographically related to the bacteria but unrelated to the inflammatory infiltrate. Disintegration and loss of apical mucus with formation of epithelial pits was seen in nearly all cases. Other changes included microerosion, conventional erosion, and frank ulceration. Only the disintegration of apical mucus, epithelial pit, and microerosion were specific for HP colonization. These conditions were absent in areas not colonized by HP and in 79 consecutive HP-negative gastric biopsies seen during the same study period. The epithelial degenerative changes in HP-colonized gastric mucosa are easy to recognize in routine hematoxylin-eosin-stained sections and they could serve as histologic guides to the localization of the bacteria. It is proposed that HP-colonized gastric mucosa is a distinct pathologic entity with a pathologic spectrum ranging from active chronic gastritis to erosion and frank ulcer. Damage to the mucin-containing portion of the gastric epithelial cells appears to be the basic cytopathologic effect of HP on the gastric mucosa. As effective specific treatment for HP infection is available, identification of HP colonization in gastric biopsies should be attempted in all cases of gastritis and gastric ulcer.

Adolescent↗
PubMed1992

Spectrum of morphologic changes in lymph nodes attributable to fine needle aspiration.

Fine needle aspiration biopsy (FNAB) is a commonly used diagnostic tool for the investigation of lymphadenopathy, but little has been written about the morphologic changes resulting from this procedure and whether these changes interfere with subsequent histologic assessment. We therefore reviewed the histologic sections of a consecutive series of lymph node biopsies with previous FNAB. Ten out of 230 such cases showed changes attributable to FNAB. In four cases, hemorrhage accompanied by various stages of organization was seen, with a linear needle tract being identified in two of them. Proliferation of spindle cells around the hemorrhagic foci could raise a concern for Kaposi's sarcoma. Three cases showed segmental infarction of the nodal parenchyma, characterized by a wedge-shaped area of lymphocyte depletion and hemorrhage. Three cases showed total coagulative necrosis, which was attributable to the effects of FNAB rather than to spontaneous occurrence because the aspirates yielded abundant viable large atypical lymphoid cells. These three cases of total infarction were proven to be large-cell lymphoma upon subsequent biopsies. We conclude that the FNAB procedure may rarely affect histologic assessment of lymph nodes when there is florid myofibroblastic proliferation or total infarction. The latter complication is more likely to occur in lymph nodes involved by malignant lymphoma.

Adult↗
PubMed1992

Neural invasion in intraductal carcinoma of the breast.

Although perineural invasion in a malignancy favors the diagnosis of invasive over in situ carcinoma, we report a case of cribriform intraduct carcinoma of the breast showing perineural invasion. The in situ nature of the lesion is supported by the finding of an intact actin-positive myoepithelial cell layer around the cribriform growths and the preservation of lobular architecture.

Aged↗
PubMed1992

CD56 (NKH1)-positive hematolymphoid malignancies: an aggressive neoplasm featuring frequent cutaneous/mucosal involvement, cytoplasmic azurophilic granules, and angiocentricity.

CD56 (NKH1) expression is a rare phenomenon in malignant lymphomas, mostly confined to those occurring in the nasal or nasopharyngeal region. In this study we provide a detailed clinicopathologic analysis of nine patients with CD56-positive hematolymphoid malignancies occurring in sites other than the upper aerodigestive tract. The disease occurred predominantly in young and middle-aged men (mean age, 40 years) who often presented with swinging fever, skin rash, and/or hepatosplenomegaly, usually in the absence of peripheral lymphadenopathy. There was frequent involvement of the skin and mucosal sites, such as the salivary gland, lungs, and small intestine. The disease pursued a highly aggressive course, with most patients dying within weeks despite cytotoxic therapy. Although the cytologic appearances and immunophenotypic profile varied from case to case, the group of tumors could be unified by two morphologic features, namely, the presence of azurophilic granules in the cytoplasm of the neoplastic cells and the frequent occurrence of angiocentric and angiodestructive infiltrates. Since CD56 reactivity appears to confer a poor prognosis in hematolymphoid malignancies, we recommended inclusion of CD56 antibody in the routine panel for immunophenotypic analysis.

Adult↗