Biomedical subjects

Timothy Craig Allen

Publications and source records attributed to Timothy Craig Allen.

7 recordsLinked to original sources

PubMed2006

Synchronous pulmonary carcinoma and pleural diffuse malignant mesothelioma.

Synchronous pulmonary carcinoma and pleural diffuse malignant mesothelioma is rare. Cases from the archives of 2 large referral centers were reviewed to identify cases of synchronously occurring pulmonary carcinoma and pleural diffuse malignant mesothelioma. Three cases of synchronous pulmonary carcinoma and pleural diffuse malignant mesothelioma were identified from more than 16,000 pleuropulmonary cases and were reviewed for demographic, clinical, radiographic, histologic, and immunohistochemical findings. The patients were men who were 63, 67, and 77 years old. Two had positive smoking histories; the smoking history of the other patient is unknown. One patient had a positive history of asbestos exposure; one patient had no history of asbestos exposure; and one patient's history of asbestos exposure is unknown. The patients underwent surgery for treatment of adenocarcinoma that was diagnosed preoperatively. Two of the adenocarcinomas were of a predominantly bronchioloalveolar pattern. No diffuse malignant mesothelioma was identified preoperatively. Diffuse malignant mesothelioma was suspected on the basis of pleural involvement by tumor with histology differing from that of the adenocarcinoma. Tumor immunostaining supported the diagnoses. The average survival after diagnosis was 6 weeks or less. In summary, the paucity of cases at 2 large referral centers and the paucity of cases reported in the English language literature highlights the rarity of synchronous pulmonary carcinoma and pleural diffuse malignant mesothelioma. These synchronous neoplasms occur in patients who have risk factors for both neoplasms independently. Length of survival following diagnosis is bleak.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2005

Localized malignant mesothelioma.

Localized malignant mesotheliomas are uncommon sharply circumscribed tumors of the serosal membranes with the microscopic appearance of diffuse malignant mesothelioma but without any evidence of diffuse spread. Little is known about their behavior. We report 23 new cases. The mean age at presentation was 63 years, and the sex ratio was approximately 2:1 (male/female). Twenty-one tumors were pleural and 2 were peritoneal. Sixteen tumors reproduced microscopic patterns of diffuse epithelial mesotheliomas, 6 had mixed epithelial and sarcomatous patterns, and 1 was purely sarcomatous. After surgical excision of the tumor, 10 of 21 patients with follow-up data were alive without evidence of disease from 18 months to 11 years after diagnosis. Patients who died had developed local recurrences and metastases, but none had diffuse pleural spread. Localized malignant mesotheliomas should be separated from diffuse malignant mesotheliomas because of their localized presentation, quite different biologic behavior, and far better prognosis.

Adult↗

PubMed2005

Recognition of histopathologic patterns of diffuse malignant mesothelioma in differential diagnosis of pleural biopsies.

CONTEXT: Diffuse malignant mesothelioma is generally divided into 3 basic histologic types--epithelial, biphasic, or sarcomatous. However, a great diversity of histologic patterns exists within these 3 basic histologic types. DESIGN: The diverse histologic patterns of diffuse malignant mesothelioma are briefly described, including infrequently encountered patterns. RESULTS: The histologic patterns of diffuse malignant mesothelioma provide a wide variation of features for the pathologist to consider in the differential diagnosis of a pleural biopsy. CONCLUSION: Pathologists should be aware of the varied histologic patterns of diffuse malignant mesothelioma when evaluating pleural biopsies.

Biopsy↗

PubMed2005

Review and update of uncommon primary pleural tumors: a practical approach to diagnosis.

OBJECTIVE: We address the current classifications and new changes regarding uncommon primary pleural tumors. Primary pleural tumors are divided according to their behavior and are discussed separately as benign tumors, tumors of low malignant potential, and malignant neoplasms. DATA SOURCES: Current literature concerning primary pleural neoplasms was collected and reviewed. STUDY SELECTION: Studies emphasizing clinical, radiological, or pathologic findings of primary pleural neoplasms were obtained. DATA EXTRACTION: Data deemed helpful to the general surgical pathologist when confronted with an uncommon primary pleural tumor was included in this review. DATA SYNTHESIS: Tumors are discussed in 3 broad categories: (1) benign, (2) low malignant potential, and (3) malignant. A practical approach to the diagnosis of these neoplasms in surgical pathology specimens is offered. The differential diagnosis, including metastatic pleural neoplasms, is also briefly addressed. CONCLUSIONS: Uncommon primary pleural neoplasms may mimic each other, as well as mimic metastatic cancers to the pleura and diffuse malignant mesothelioma. Correct diagnosis is important because of different prognosis and treatment implications for the various neoplasms.

Biopsy↗

PubMed2005

Frozen section of lung specimens.

CONTEXT: Frozen section of lung tissue is performed to guide the surgeon in subsequent therapy. DESIGN: Practical experience in frozen section of the lung was reviewed in the medical literature and from the records of several academic hospitals. RESULTS: Most frozen sections of the lung are performed for evaluation of a solitary nodule, a mass, or the surgical margins of a resection. Frozen section may also be used to assess the adequacy of a lung wedge biopsy taken for later diagnosis of a condition. CONCLUSION: The pathologic evaluation of intraoperative pulmonary lesions is indicated for the differential diagnosis of pulmonary nodules and masses, both neoplastic and nonneoplastic, surgical resection margins, and mediastinal lymph nodes. The most worrisome pitfalls involve differentiating benign reactive atypia from malignancy on frozen section.

Diagnosis, Differential↗

PubMed2005

Cytomegalovirus infection masquerading as carcinoma in a lung transplant patient.

In lung transplant patients, most infections produce radiographically diffuse or lobar infiltrates. Solitary nodules suggesting neoplasm may arise in lung transplant patients with lung infections. We describe a 45-year-old woman who underwent bilateral lung transplantation to treat bilateral bronchiectasis and lung fibrosis resulting from Hodgkin disease. Five months later, a solitary mass was identified on chest radiograph in the left upper lobe and left superior mediastinum. Low-power examination of wedge biopsies of the mass showed a florid proliferation of cells with clear to bubbly to eosinophilic cytoplasm and moderate nuclear atypia, proliferating fibroblasts, and necrosis, suggesting a clear cell carcinoma (possibly metastatic renal cell carcinoma). Intranuclear inclusions compatible with cytomegalovirus were identified on high-power examination and confirmed by immunohistochemistry. In lung transplant patients, a cytomegalovirus infection may mimic malignancy both radiographically and on initial histopathologic examination.

Carcinoma↗

PubMed2004

Pulmonary and ophthalmic involvement with Erdheim-Chester disease: a case report and review of the literature.

Erdheim-Chester disease is a rare nonfamilial histiocytic disorder of unknown etiology with characteristic long bone findings. The 3-year survival rate for patients with Erdheim-Chester disease is 50%. Approximately 50% of patients have disease involvement in other tissues, including skin, retro-orbital and periorbital tissues, pituitary-hypothalamic axis, heart, kidney, retroperitoneum, breast, skeletal muscle, and sinonasal mucosa; about 20% of patients have lung involvement. Prognosis generally depends on the extent of the extraosseous disease. For patients with lung involvement, gender distribution is equal, but men typically present at an older age than do women. Approximately 80% of patients present with dyspnea, and most patients have diffuse interstitial infiltrates and pleural and/or interlobar septal thickening on chest radiology. Characteristic lung histopathology includes the accumulation of histiocytes with variable amounts of fibrosis and a variable lymphoplasmacytic infiltrate in a lymphangitic distribution. Immunostains are diagnostically useful, showing immunopositivity for CD68 and factor XIIIa and immunonegativity for CD1a. Birbeck granules are uniformly absent ultrastructurally.

Dyspnea↗