Detection and species identification of mycobacteria in paraffin sections of lung biopsy specimens by the polymerase chain reaction.

The authors analyzed 25 paraffin-embedded lung biopsy specimens for mycobacterial DNA by the polymerase chain reaction (PCR) from patients with pulmonary mycobacterial infection demonstrated by acid-fast stain, culture, or both. DNA was extracted from 4 microM unstained paraffin sections by proteinase K digestion followed by freeze-fracturing and amplified by nested PCR with primers for the mycobacterial 65-kDa antigen gene. Mycobacterial DNA was detected in 7 of 7 wedge and 9 of 18 transbronchial biopsy specimens by PCR. Nested PCR with direct visualization on an agarose gel was as sensitive as Southern blot hybridization. Serial dilution studies demonstrated that nested PCR could detect DNA amplified from 4-8 acid-fast organisms from a paraffin section. Restriction enzyme digestion of the amplified PCR product differentiated Mycobacterium tuberculosis from Mycobacterium avium-intracellulare. Polymerase chain reaction can detect low numbers of acid-fast organisms in paraffin sections and confirm and presumptively speciate mycobacterial infection when cultures are negative or not obtained.

Ischemic fasciitis: a juxta-skeletal fibroblastic proliferation with a predilection for elderly patients.

We are reporting six examples of a distinctive reactive fibroblastic proliferation occurring predominantly in elderly bed-ridden or convalescent patients that presents as an ill-defined mass often overlying a bony prominence or in close apposition to the periosteum of bone. Unlike conventional fasciitis, the lesion achieves a relatively larger size and is characterized by a biphasic appearance with an outer fringe of mitotically active fibroblasts and capillaries circumscribing a central area of liquefactive and focally coagulative necrosis. Follow-up information in all patients indicated no evidence of aggressive behavior. We believe these lesions arise on an ischemic basis, similar to a decubitus ulcer, from long-standing or intermittent pressure on the soft tissue structures. Because of their large size and close proximity to bone, they are commonly mistaken for a sarcoma.

Primary intestinal lymphoma in Crohn's disease: minute tumor with a fatal outcome.

A 54-yr-old man with a 22-yr history of Crohn's disease was found to have a microscopic focus of immunoblastic lymphoma within a segment of small bowel resected to relieve intestinal obstruction. There was no other clinically evident disease. Thirty months later, he developed axillary adenopathy with recurrent lymphoma of the same immunophenotype (IgA lambda) and was given combination chemotherapy, with complete clinical response. Lymphoma recurred 6 months later in the axilla and progressed rapidly over the next 3 months, despite chemotherapy. He developed extensive mediastinal, mesenteric, and retroperitoneal disease with malignant ascites and died 39 months after diagnosis of the incidentally discovered bowel mucosal primary tumor.

Expression of growth factors and growth factor receptors in soft tissue tumors. Implications for the autocrine hypothesis.

According to the autocrine hypothesis of cell growth, tumors, in contrast to normal tissue, might simultaneously express both a growth factor and its receptor, resulting in autoregulation and autostimulation of growth. In a related hypothesis, expression of either a growth factor or receptor might allow a tumor to escape exogenous controls on growth, and thereby correlate with malignant potential. Using immunohistochemistry, we investigated these hypotheses in 69 human soft tissue tumors (STT) by assaying for the expression of nerve growth factor and receptor, epidermal growth factor and receptor and platelet-derived growth factor. Both benign (B) and malignant (M) STT expressed a variety of factors and receptors. However, the frequency of any growth factor expression (90% M versus 55% B, p = 0.002) and of multiple factors (59% M versus 24% B, p = 0.006) was significantly greater in malignant tumors. Similarly, expression of any growth factor receptor (73% M versus 31% B, p = 0.001) and of multiple receptors (35% M versus 3% B, p = 0.002) was significantly more frequent in malignant STT. In terms of the autocrine hypothesis, growth factor/receptor co-expression was significantly more common in malignant STT (63% M versus 17% B, p = 0.0002). We conclude that (a) expression of both single and multiple growth factors and receptors was significantly more frequent in malignant STT; (b) support for an autocrine growth mechanism through simultaneous factor/receptor co-expression can be found in both benign and malignant STT; (c) co-expression, however, was more frequent in the malignant tumors; and (d) overall, growth factor and receptor expression, as well as co-expression, was related to biologic potential among human soft tissue tumors.

Expression of nerve growth factor receptor in paraffin-embedded soft tissue tumors.

Identification of growth factors and receptors in mesenchymal tumors may be crucial to understanding of growth regulation in sarcomas. During an immunohistochemical study of the expression of growth factors and receptors in human soft tissue tumors (STT), only 1 antisera capable of working in paraffin-embedded tissue was noted. A detailed study of 141 STT was undertaken to determine the frequency of expression of nerve growth factor receptor (NGF-R), its specificity and sensitivity for neural tumors, and the effect of fixation on detection. In normal mesenchymal tissue, only nerve sheath and perivascular staining was seen. No immunoreactivity was seen in many tumors including rhabdomyosarcoma, angiosarcoma, liposarcoma, Ewing's sarcoma, and alveolar soft part sarcoma. Less than 15% of tumors of smooth muscle, fibrous, or fibrohistiocytic origin showed immunoreactivity, usually focal. In contrast, a high frequency of immunoreactivity was noted in tumors of neural origin (74%). This included granular cell tumors (100%), Schwannoma/neurofibroma (91%), malignant Schwannoma (78%), neuroblastoma/neuroepithelioma (60%), and paraganglioma (57%). A high rate of reactivity was also seen in synovial sarcomas (80%), undifferentiated sarcomas (60%), and hemangiopericytomas (43%), suggesting a potential relationship to the neural phenotype. Among the neural tumors, Bouin's fixation was superior to formalin, suggesting that immunoreactivity for NGF-R is affected by fixation. This antibody may be a useful adjunct marker diagnostically.

MR imaging of osteoid osteoma of the talus.

Magnetic resonance (MR) imaging of the painful ankle of a 15-year-old boy revealed the nidus of a subarticular osteoid osteoma of the talus along with markedly abnormal signal intensity in the neighboring bone marrow. This MR appearance correlated with alterations in the neighboring bone marrow documented by histopathologic examination.