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T W Shek

Publications and source records attributed to T W Shek.

At least 55 records · Page 3Linked to original sources
PubMed2000

CD-30 positive peripheral T-cell lymphoma of the Waldeyer's ring.

We describe a patient with peripheral T cell lymphoma of the Waldeyer's ring that ran a highly aggressive course. This is followed by a discussion on the differential diagnoses of nasal T/NK cell lymphoma and Ki-1 ALCL, based on clinical and pathological features.

Adult↗
PubMed1999

Osteochondroma and secondary synovial osteochondromatosis.

Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period. Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding bursal and secondary SOC are reviewed.

Adult↗
PubMed1999

Osteogenic sarcoma with skeletal muscle metastases.

Two cases of osteogenic sarcoma with skeletal muscle metastases are described. A 40-year-old woman presented with progressive swelling of both calves and a soft tissue back lump. She had been diagnosed with mandibular chondroblastic osteogenic sarcoma 6 years earlier. Radiographs showed calcified masses. MRI scans and bone scintigraphy revealed multiple soft tissue masses in both calves. Bone scintigraphy also showed uptake in the back lump, right thigh and left lung base. Biopsy confirmed metastatic chondroblastic osteogenic sarcoma, which initially responded well to chemotherapy. However, the metastatic disease subsequently progressed rapidly and she died 21 months after presentation. The second case concerns a 20-year-old man who presented with a pathologic fracture of the humerus, which was found to be due to osteoblastic osteogenic sarcoma. He developed cerebral metastases 17 months later, followed by metastases at other sites. Calcified masses were subsequently seen on radiographs of the abdomen and chest. CT scans confirmed the presence of densely calcified muscle metastases in the abdominal wall, erector spinae and gluteal muscles. The patient's disease progressed rapidly and he died 30 months after presentation.

Adult↗
PubMed1999

The role of trisomy 8 in the pathogenesis of chronic eosinophilic leukemia.

A case of chronic eosinophilic leukemia (CEL) manifesting as spinal cord compression by an extradural eosinophilic chloroma in a 32-year-old Chinese man was presented, who subsequently developed extramedullary transformation at the skin and then peritoneal cavity. Cytogenetic study of bone marrow cells at diagnosis showed a clonal karyotypic abnormality of trisomy 8 (+8), which on fluorescence in situ hybridization (FISH) was shown to be present in a clone of abnormal eosinophils, hence showing the neoplastic nature of the eosinophilic proliferation. There was another population of abnormal eosinophils that did not show +8. At blastic transformation, all blast cells in ascitic fluid were shown by FISH to harbor +8. These findings suggest that +8 in this case may have arisen from clonal evolution and is not the primary genetic event in leukemogenesis, but +8 most probably imparts a further survival advantage to the clone responsible for subsequent blastic transformation.

Adult↗
PubMed1999

Chondromyxoid fibroma of skull base: a tumour prone to local recurrence.

Chondromyxoid fibroma of the skull base is extremely uncommon. Sometimes involvement of the nasal cavity may occur and the patients may present with nasal symptoms. The biological behaviour of this tumour has not been well studied, primarily because of the limited number of reported cases and the short duration of follow-up. We report a histologically confirmed case of chondromyxoid fibroma of the skull base that recurred repeatedly over a 10-year period after the initial operation. Histologically it showed identical morphology to the original tumour with no evidence of histological progression or dedifferentiation. Ultrastructurally, the spindle tumour cells in the fibromyxoid area showed dual chondroblastic and fibroblastic differentiation, suggesting that these spindle fibroblastic cells and the better differentiated chondroid cells were of the same cell type with different histological morphology.

Child↗
PubMed1999

Metanephric adenofibroma: report of a case and review of the literature.

The recent recognition of a variety of pediatric renal tumors of different biologic behavior places an ever-increasing demand on the surgical pathologist for an accurate diagnosis. Although metanephric adenofibroma is one of the rarest benign renal tumors, the clinical importance of correctly diagnosing it cannot be overemphasized because it can potentially be mistaken as Wilms' tumor. We describe the clinical, radiologic, and pathologic features of a case of metanephric adenofibroma and discuss its differential diagnosis. The neoplasm was composed of two discrete components: a major fibroblastic element and a minor immature epithelial element. The latter formed a small nodule beneath the renal capsule, which could barely be detected by magnetic resonance imaging. This subcapsular nodule, however, was slightly soft and tan and was distinctly different from the white, whorled cut surface of the main tumor. It was formed by closely packed small immature epithelial cells in a slightly edematous background, which was histologically identical to metanephric adenoma and closely resembled epithelial Wilms' tumor. Unlike Wilms' tumor, however, the epithelial cells were very bland with no mitoses. The main bulk of the tumor was formed by spindle fibroblastic cells that were cytologically similar to the spindle cells in congenital mesoblastic nephroma. The tumor, however, was well demarcated without the irregular infiltrating edges of congenital mesoblastic nephroma. In contrast to the randomly distributed epithelial element throughout the stromal component in previous reported cases of metanephric adenofibroma, our finding of the exceedingly small and discrete epithelial component expands the known histologic spectrum of the disease. In addition, the presence of such minute epithelial nodule underscores the importance of diligent pathologic examination and careful sampling of tissue for histologic examination.

Adenofibroma↗
PubMed1999

Interdigitating dendritic cell tumor of the testis: a novel testicular spindle cell neoplasm.

Interdigitating dendritic cell tumor is an extremely rare neoplasm that mainly occurs in lymph nodes. An example of such a tumor in the testis, a hitherto unreported site, is described. Grossly, the tumor was light tan with a uniform solid appearance, replacing virtually the entire testis. Microscopically, it was formed by whorls and fascicles of spindle cells intermingling with small lymphocytes. Such a histologic appearance can, however, mimic a wide variety of other tumors and tumor-like lesions, among which mesenchymal sarcoma, spindle cell carcinoma, follicular dendritic cell tumor, and inflammatory pseudotumor are the main differential diagnoses. Immunohistochemical studies showed that the spindle tumor cells were strongly and diffusely positive for S-100 protein and vimentin. They were also focally positive for CD68 and CD4, but were uniformly negative for leukocyte common antigen, CD1a, CD3, CD20, CD21, CD23, CD34, CD35, actin, desmin, HMB45, cytokeratins, and placental alkaline phosphatase. Ultrastructurally, the tumor cells possessed complex interdigitating cytoplasmic dendritic processes, with abundant rough endoplasmic reticulum and mitochondria in their cytoplasm. An in situ hybridization study for Epstein-Barr virus was negative. The pathologist should be aware of such an entity and consider it in the list of differential diagnoses for unusual spindle cell lesions with a significant background population of small lymphocytes. However, because of its nonspecific histologic appearance, additional immunohistochemical and electron microscopic studies are generally required for its definitive diagnosis.

Adolescent↗
PubMed1999

The effect of using shorter echo times in MR imaging of knee menisci: a study using a porcine model.

OBJECTIVE: Increasingly shorter TEs are being used for T1-weighted and proton density-weighted sequences in MR imaging of the knee. This study aims to evaluate the effect of a short TE on meniscal signal intensity. MATERIALS AND METHODS: Thirty porcine knees were imaged with a 1.5-T MR scanner using spin-echo T1-weighted and proton density-weighted sequences. TR was kept constant at 700 msec for T1-weighted and 2200 msec for proton density-weighted sequences. For each set of sequences, sagittal images were obtained using these TE values: 9, 12, 16, 20, and 25 msec. Imaging parameters, such as slice thickness and interslice gap, number of excitations, matrix size, and field of view, were identical for each set of sequences. Using a fixed window level and width, we assessed the anterior and posterior horns of the medial meniscus for signal hyperintensity at each TE value. Signal intensity was also measured in eight knees. The menisci were then dissected and examined grossly and histopathologically. RESULTS: Intrameniscal signal intensity increased progressively with shorter TEs. At a TE of 9 msec, signal hyperintensity was present in 100% of T1-weighted and 96.7% of proton density-weighted images. At a TE of 12 msec, signal hyperintensity was seen in 86.7% of T1-weighted and 80% of proton density-weighted images. At a TE of 16 msec, increased signal intensity was seen in only 3.3% of T1-weighted and 6.6% of proton density-weighted images. At TEs of 20 and 25 msec, increased signal intensity was seen in none of the T1-weighted and proton density-weighted images. Meniscal signal intensity increased exponentially at very short TE values. All menisci were found to be normal on gross and histopathological examination. CONCLUSION: Spurious signal hyperintensity appears in normal menisci at short TE values. Images acquired with short TEs should be interpreted with caution, and a TE of 16 msec or more is recommended.

Animals↗
PubMed1998

Follicular dendritic cell sarcoma and interdigitating reticulum cell sarcoma: a review.

Neoplasms of reticular dendritic origin are extremely rare and include the follicular dendritic cell sarcoma (FDCS) and the interdigitating reticulum (or dendritic) cell sarcoma (IDCS). In this article, we review the literature pertaining to the two diseases and describe clinical observations and salient pathologic features, including information provided by authors of FDCS and IDDCS reports. We performed a computerized database search for published articles regarding FDCS and IDDCS. The articles were evaluated critically by the authors. Simple descriptive statistics were used to analyze the data. There are 51 cases of FDCS and 21 cases of IDDCS that are well documented in the literature. The pathologic diagnosis of FDCS and IDDCS is often challenging and requires morphologic, immunophenotypic, cytochemical, and electron-microscopic analysis. Patients with FDCS usually present with cervical or axillary lymphadenopathy, but extranodal disease has been described. In at least some patients, preexisting Castleman's disease has been recognized. Resected localized disease may be prevented from recurrence by consolidative radiotherapy. Chemotherapy regimens have shown nondurable antitumor activity in FDCS. Patients with IDDCS usually present with lymphadenopathy. The clinical course of IDDCS has been variable, but it seems to be more aggressive than that of FDCS. Variable degrees of remission may be achieved with chemotherapy. FDCS and IDDCS are rare neoplasms that may pose difficulty in pathologic diagnosis. IDDCS seems to display a more aggressive behavior than FDCS. Patients with IDDCS and FDCS can eventually die of disease progression. The role of chemotherapy and radiotherapy is not clearly defined.

Dendritic Cells↗
PubMed1998

Intra-abdominal follicular dendritic cell tumour: a rare tumour in need of recognition.

AIMS: Neoplasms of follicular dendritic cells are uncommon and the majority of them occur in lymph nodes. Rarely, they may occur inside the abdominal cavity. We describe two examples of intra-abdominal follicular dendritic cell (FDC) tumour. One involved the liver and the other involved the ampulla of Vater. Our aims are to complement the current understanding on this disease and to alert histopathologists and clinicians to this rare entity. MATERIALS AND RESULTS: The clinical and radiological findings of the two cases of intra-abdominal follicular dendritic cell tumours were reviewed. The resected specimens were examined macroscopically and microscopically. Immunohistochemical studies, ultrastructural examination and in situ hybridization for Epstein-Barr virus were also performed. Both tumours could not be accurately diagnosed before pathological examination of the resected specimens. The soft to slightly firm consistency of the tumours resembled that of fixed brain tissue, and was distinctly different from hepatocellular carcinoma or pancreatic carcinoma. The fascicular arrangement of syncytial plump to spindle cells in a background of mixed inflammatory cells was the initial clue to the diagnosis, which was confirmed by the immunoreactivity of the tumour cells to follicular dendritic cell markers (CD21 and CD35), and by the demonstration of focal intercellular desmosome-like junctions between the complex cytoplasmic processes of the tumour cells. The tumour cells in the liver tumour also showed presence of Epstein-Barr virus on in situ hybridization study. CONCLUSIONS: Awareness of the entity and the ability to recognize this tumour by histopathologists are emphasized because the tumour closely mimics a wide variety of other tumours and tumour-like lesions. Similar to the other reported FDC tumours of the liver, our case of hepatic follicular dendritic cell tumour is also positive for Epstein-Barr virus, suggesting that the virus may play a role in its pathogenesis.

Adult↗
PubMed1998

Combined hepatocellular-cholangiocarcinoma: a clinicopathological study.

Combined hepatocellular-cholangiocarcinoma (HCC-CC) is an uncommon form of primary liver cancer having features of both hepatocellular and biliary epithelial differentiation. We reviewed 21 cases of this tumour diagnosed between 1972 and 1996 (patient age range 16-79 years; mean patient age 49.7 years; 18 male and three female patients). Histologically, the majority (n = 18) of tumours were 'mixed' tumours, in which areas of hepatocellular and biliary epithelial differentiation were intimately mixed within the same tumours. Two patients had separate tumours in which discrete nodules of HCC and CC occurred in the same livers. One patient had a 'fibrolamellar' tumour that histologically simulated the fibrolamellar variant of HCC, but some of the tumour cells were mucin-producing cells. Of the 21 cases, mucin was demonstrable in 16 and, in the few mucin-negative tumours, electron microscopic studies confirmed the presence of the dual differentiation. The tumours frequently exhibited an invasive character with frequent venous permeation, direct invasion into adjacent liver parenchyma and tumour microsatellite formation, similar to that of ordinary HCC. Histological evidence of cirrhosis or chronic hepatitis was present in 77.8% of patients and 75% of patients were hepatitis B surface antigen positive. Raised serum alpha-fetoprotein (AFP) levels (above 300 ng/mL) were present in 61.5% of patients and AFP was detected immunohistochemically in 55% of tumours. The overall survival times of patients with HCC-CC were short. In conclusion, HCC-CC showed clinical and pathological features more akin to those of ordinary HCC than to CC.

Adult↗
PubMed1998

Imaging of follicular dendritic cell tumours of the liver.

Follicular dendritic cell tumour of the liver is a recently recognized entity. To date, only two cases have been described, both in the pathology literature. Histologically, it resembles an inflammatory pseudotumour and immunohistochemical and ultrastructural studies are required for its diagnosis. The ultrasound, computed tomography and angiographic features of two cases of follicular dendritic cell tumour of the liver are described in detail. One of the patients had multiple recurrences of this tumour. The imaging features are very similar to those of hepatocellular carcinoma. As follicular dendritic cell tumour is considered to be of low-grade malignant potential, in contrast to the dismal prognosis for hepatocellular carcinoma, it is important to be able to accurately distinguish between the two types of tumour prior to initiating definitive therapy.

Adult↗