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Biomedical subjects

M W Pak

Publications and source records attributed to M W Pak.

At least 19 recordsLinked to original sources
PubMed2001

Unusual T- and T/NK- cell non-Hodgkin's lymphoma of the larynx: a diagnostic challenge for clinicians and pathologists.

BACKGROUND: Lymphomas of T-cell and T/natural killer (T/NK)-cell types rarely involve the larynx. Early symptoms are subtle and nonspecific, and confirmation of the diagnosis is often difficult. Because of the rarity of this disease entity, the optimal management remains controversial. METHODS: The case records of patients with the diagnosis of lymphoma involving the larynx were retrospectively reviewed. Details of the pathologic condition, the difficulties in diagnosis, and treatment were presented. RESULTS: One case of T-cell lymphoma (Lennert's lymphoma subtype) and two cases of T/NK-cell lymphomas involving the larynx were presented. The diagnoses were all difficult to establish. All three patients received either multiagent chemotherapy or radiotherapy as the first-line treatment. They all died of the disease within 32 months of diagnosis. CONCLUSIONS: T- and T/NK-cell non-Hodgkin's lymphoma of the larynx is a diagnostic challenge for clinicians and pathologists. Conventional chemotherapy or radiotherapy has not been effective. A more aggressive therapy should be considered.

Adult↗
PubMed2001

In vivo diagnosis of nasopharyngeal carcinoma using contact rhinoscopy.

OBJECTIVES: To evaluate the potential use of contact endoscopy for the diagnosis of nasopharyngeal carcinoma (NPC). STUDY DESIGN: Prospective study to examine the nasopharynx of 30 patients with nasopharyngeal carcinoma and 18 subjects with normal nasopharynx in a clinic setting using contact rhinoscopes (Karl Storz, Tuttlingen, Germany, 7215 AA, 00 and 7215 BA, 300; 23 cm long; 4 mm in diameter). METHODS: The superficial cells of the normal nasopharynx and the nasopharyngeal tumors were stained with 1% methylene blue and examined with contact rhinoscopes at high magnifications (x 60 and x 150). The areas under examination were then biopsied. The contact endoscopic images were compared with the corresponding hematoxylin and eosin-stained histologic sections of the biopsied tissues. RESULTS: Sixty-six procedures were performed in 48 patients. The images of normal pseudostratified ciliated epithelium and squamous epithelium were readily recognized by contact endoscopy in all subjects with normal nasopharynx (10 men and 8 women; mean age, 51.9 y). Twenty-six of 30 patients with NPC (86.6%; 18 men and 8 women; mean age, 50.6 y) were successfully examined by contact endoscopy under local anesthesia. In these 26 patients, two patterns of malignant cells were identified with contact endoscopy. The patterns of contact endoscopic images corresponded well with the histologic findings. CONCLUSION: Contact endoscopy is an accurate and reliable office-based procedure, which allows for in-vivo diagnosis of nasopharyngeal carcinoma.

Adult↗
PubMed2001

Lateralized carotid artery: an unusual cause of pulsatile tinnitus.

We describe the case of a patient who had a pulsatile tinnitus that was caused by a laterally displaced internal carotid artery. Her condition was treated with the use of a hearing did, which suppressed the tinnitus. We also review the literature on laterally displaced internal carotid arteries, and discuss their differentiation from a congenitally aberrant artery.

Carotid Artery, Internal↗
PubMed2001

Cowden's disease with vocal fold involvement.

Cowden's disease is a hereditary disorder characterized by oropharyngeal fibrosis and multiple hamartomas with potential malignant changes. We treated a 47-year-old man who had fibrotic lesions on the left vocal fold and an extensive amount of papillomatous lesions on the mucosa of the lips, tongue, and pharyngeal wall and on the skin of the axillae and buttocks. The pattern of distribution and the histopathologic features of these mucocutaneous lesions were diagnostic of Cowden's disease. To the best of our knowledge, this is the first reported case of Cowden's disease involving a vocal fold.

Diagnosis, Differential↗
PubMed2000

Morphometric analysis of argyrophilic nucleolar organizer regions (AgNORs) in nasopharyngeal carcinoma.

BACKGROUND: Nucleolar organizer regions (NORs), which are loops of DNA containing ribosomal RNA genes, have been shown to correlate with cell proliferation and malignant transformation. Conventional eyeball measurement of silver staining NORs (AgNORs) is time-consuming and subject to error. The diagnostic value of AgNOR area in nasopharyngeal carcinoma (NPC) by computer-assisted morphometric analysis is evaluated. METHODS: Silver-staining of NORs was applied to 23 paraffin sections of NPC containing both normal squamous epithelial and malignant cells. Various parameters of the AgNORs of these two cell types were analyzed by a computer-assisted image analysis system and then compared. RESULTS: The mean AgNOR area, AgNOR/nuclear area ratio, and AgNOR area/count ratio of malignant tumors were statistically significantly higher than those for the normal epithelium. There was no significant difference in the AgNOR counts between the two cell types. CONCLUSIONS: Computer-assisted morphometric analysis of AgNOR is an objective and reliable assessment method applicable to paraffin sections of NPC. The AgNOR area and its derivatives may aid in the diagnosis of NPC.

Adult↗
PubMed2000

Fish bone inhalation in infancy.

Inhalation of sharp bones by infants is an uncommon but hazardous occurrence. management relies not only on a high index of clinical suspicion and timely treatment but also demands expertise in therapeutic bronchoscopy. The potential complications and the management of this condition are reviewed.

Animals↗
PubMed2000

Prognostic significance of argyrophilic nucleolar organizer regions in nasopharyngeal carcinoma.

Increased expression of argyrophilic nucleolar organizer regions (AgNORs) has been identified in certain malignant tumors including nasopharyngeal carcinoma (NPC). However, its prognostic significance in NPC is uncertain and remains to be evaluated. To address this we silver-stained 63 paraffin sections of NPC cases, and examined the correlation between AgNOR count and area, calculated by the CAS 200 image analysis system, and tumor behavior, locoregional control, and survival of patients. The mean AgNOR count and area were 1.62 +/- 0.31 and 3.98 +/- 11.4 microm2, respectively. The AgNOR area was positively associated with T stage (r = 0.26, P = 0.04). The Mann-Whitney test confirmed no significant difference in AgNOR area and count between patients with different outcomes. Multivariate analysis using the Cox proportional hazard model showed neither AgNOR count nor area to be significant predictors of actuarial survival or disease-free survival. It is concluded that AgNOR does not have an independent and significant prognostic value in NPC. AgNOR expression may be merely a reflection of malignant phenotype as well as cellular activity but not necessarily the ultimate behavior of the tumor.

Adolescent↗
PubMed2000

Cochlear deafness in a Chinese family with Fechtner's syndrome.

OBJECTIVE: To identify the nature of the hearing impairment in the members of a Chinese family with Fechtner's syndrome. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: A Chinese family with a variant of Alport's syndrome: high-tone sensorineural hearing loss, proteinuria, macrothrombocytopenia, and ocular disease. INTERVENTIONS: The diagnosis of Fechtner's syndrome was confirmed by the characteristic ultrastructure of the Döhle-like inclusion bodies in the neutrophils of the mother and her three children. Pure-tone audiometry, evoked response audiometry (ERA), and distortion product otoacoustic emissions (DPOAE) were performed in two subjects to investigate the hearing impairment. MAIN OUTCOME MEASURE: The parameters of the ERA and DPOAEs were correlated. RESULTS: In both subjects, the ERA was within normal limits, and there were no measurable DPOAEs in frequencies >2 kHz. CONCLUSION: The hearing loss in Fechtner's syndrome is cochlear rather than neural.

Adult↗
PubMed1999

Retropharyngeal abscess. A rare presentation of nasopharyngeal carcinoma.

Early symptoms of nasopharyngeal carcinoma (NPC) can often be deceptive and confusing. Most patients with nasopharyngeal carcinoma present at an advanced stage with metastatic cervical nodes present at the time of diagnosis. A deep neck abscess as the presenting feature has not been reported. We report two cases of nasopharyngeal carcinoma which presented with retropharyngeal abscesses and persistent lymphadenopathy. These two patients illustrate that refractory lymphadenopathy, despite adequate treatment of the associated infection, should prompt a search for underlying disease. The relationship between nasopharyngeal carcinoma and retropharyngeal abscess is discussed.

Adult↗
PubMed1999

Nasal manifestation of extranodal Rosai-Dorfman disease--diagnosis and management.

Two cases of Rosai-Dorfman disease with polypoid nasal infiltration mimicking nasal tuberculosis and malignant lymphoma are reported. This rare benign disease was first described by Rosai and Dorfman in 1969 and is characterized by histiocytic proliferation. It is seldom considered in the differential diagnosis of granulomatous diseases due to its rarity and histological similarity to other diseases. Extranodal manifestations of this disease are uncommon. Although no specific treatment can guarantee a sustained remission of this disease, surgery for loco-regional lesions can result in long-term symptomatic control and restoration of function. Both patients underwent endoscopic resection of the nasal polypoid lesions and have subsequently been free of recurrence. Loco-regional infiltration of the nasal cavity by Rosai-Dorfman disease is effectively managed by endoscopic resection.

Adult↗
PubMed1998

Late complications of nasal augmentation using silicone implants.

Alloplastic nasal augmentation with silicone elastomer (Silastic) is popular in areas of Asia. Although the silicones are bio-inert, they have been implicated in a number of adverse reactions after implantation. We report our experience of three patients who presented with late complications after nasal augmentation using Silastic implants. The mechanisms of implant failure are proposed. It is advised that this material should only be used on an individual basis in carefully selected cases.

Adult↗
PubMed1996

Congenital laryngeal cysts: current approach to management.

Congenital laryngeal cysts are a rare cause of neonatal upper airway obstruction which may lead to serious morbidity and mortality if diagnosis and treatment are delayed. We reviewed our experience with nine patients over a six-year period. The annual incidence of this condition was 1.82 per 100,000 live births. The diagnosis can be confirmed safely by flexible laryngoscopy before definitive surgery is contemplated. Contrary to other studies, we found that endoscopic removal of cysts can achieve an effective cure without recurrence. Endoscopic deroofing is as effective as endoscopic excision but is technically simpler and thus is recommended as the treatment of choice.

Cysts↗
PubMed1996

Dural metastasis at medulla oblongata: a rare cause of vocal fold paralysis.

Malignancy is a major cause of vocal fold paralysis. Nevertheless, metastatic disease at the brainstem leading to high vagal paralysis is rarely encountered. We illustrate an unusual case of unilateral vocal fold paralysis caused by dural metastasis directly compressing on the nucleus ambiguus. The median position of the paralysed vocal fold is inconsistent with the Wagner and Grossman theory predicting the location of the lesion.

Brain Neoplasms↗
PubMed1987

Retinopretectal and accessory optic projections of normal mice and the OKN-defective mutant mice beige, beige-J, and pearl.

Retinal projections to the pretectal and terminal accessory optic nuclei were studied in normal wild-type mice and mutant mice with abnormal optokinetic nystagmus (OKN, Mangini, Vanable, Williams, and Pinto: J. Comp. Neurol. 241:191-209, '85). The mutants used were pearl, which exhibits an inverted OKN in response to stimulation of only the temporal retina, and beige and beige-J, which show inverted OKN in response to stimulation of only the temporal retina and, in addition, exhibit eye movements with a vertical component in response to horizontally moving, full-field stimuli. These projections were studied following intraocular injections of 3H-proline or horseradish peroxidase (HRP) with, respectively, light microscopic autoradiography or HRP histochemistry. In wild-type mice, strong contralateral retinal projections covered the entire nucleus of the optic tract, the anterior and posterior divisions of the olivary pretectal nucleus, and the posterior pretectal nucleus. Similar heavy contralateral projections were distributed over the dorsal and medial terminal nuclei of the accessory optic system. Also, terminals sparsely covered the entire neuropil of the contralateral lateral terminal nucleus in some but not all wild-type mice. The most prominent accessory optic input was to the medial terminal nucleus and was provided by the inferior fasciculus of the accessory optic tract. A typical mammalian superior fasciculus of the accessory optic system with anterior, middle, and posterior components was present. Ipsilateral label was found in anterior and posterior olivary pretectal nuclei in all of the wild-type animals, but was found inconsistently in the ipsilateral terminal accessory optic nuclei. The pattern of contralateral retinal projection to the nucleus of the optic tract and posterior pretectal nucleus in mutants was indistinguishable from that seen in the normal wild-type mice. However, retinal inputs to the ipsilateral anterior and posterior olivary pretectal nuclei were significantly reduced in pearl mutants and were exceedingly sparse in the beige and beige-J mutant mice, while the contralateral inputs to these nuclei were increased in a complementary fashion in the mutants. The labeling of the accessory optic input to the contralateral dorsal terminal nucleus appeared to be substantially reduced in all of the mutant mice. The size of the principal accessory optic fascicle, the inferior fasciculus, was significantly smaller in beige, beige-J, and pearl mice; this reduction was greater in the beige and beige-J than in the pearl mice.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗