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Biomedical subjects

Michael J Klein

Publications and source records attributed to Michael J Klein.

At least 19 recordsLinked to original sources
PubMed2006

Primary periosteal lymphoma--rare and unusual.

We describe a primary periosteal lymphoma that involved only the periosteum without affecting the adjacent medulla or the regional lymph nodes. No other lymphomatous foci were found in either the distant lymph nodes or viscera. This unusual presentation simulates the imaging appearance of surface lesions of bone, namely benign and malignant tumors, and departs from the typical appearance of primary lymphoma of bone. Therefore, this rare type of lymphoma should be considered in the differential diagnosis of surface bone lesions.

Adult↗
PubMed2006

Osteosarcoma: anatomic and histologic variants.

Osteosarcoma is the most common primary tumor of bone, yet its absolute incidence among malignant tumors is low. Within its strict histologic definition, osteosarcoma comprises a family of lesions with considerable diversity in histologic features and grade. Its prognosis is dependent not only on these parameters, but also on its anatomic site. It may occur inside the bones (in the intramedullary or intracortical compartment), on the surfaces of bones, and in extraosseous sites. Information of diagnostic or prognostic significance has not been elucidated from studies of its cytogenetics. This review summarizes the anatomic and histologic variations of osteosarcoma and offers a schema for its subclassification.

Bone Neoplasms↗
PubMed2005

Radiographic correlation in orthopedic pathology.

Radiographic correlation is an essential adjunct for the accurate diagnosis of orthopedic lesions, yet it is a skill neglected by pathologists. The purpose of this review is to demonstrate why performing this correlation is an essential part of the diagnostic process and not merely an interesting adjunct to the surgical pathology of orthopedic lesions. The relationships between x-rays and tissues are explored with an emphasis on bone and soft tissue composition and structure. In addition, the rudiments of complementary imaging studies and how to incorporate their data into diagnoses are examined.

Age Factors↗
PubMed2004

Glomus tumor of the thigh: confluent with the periosteum of the femur.

True glomus tumor is rare. In the majority of cases it involves the hand, preferring the fingertips or nail beds. We report a patient with glomus tumor of the mid-thigh who presented with severe localized pain and limp. The imaging features are discussed and the English literature reviewed.

Adult↗
PubMed2004

A solitary lesion of talus with mixed sclerotic and lytic changes: Rosai-Dorfman disease of 25 years' duration.

Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is an unusual form of histiocytic disorder predominantly affecting children and young adults. Bone lesions are infrequent. We describe a 63-year-old woman with a solitary lesion of the talus which was misdiagnosed for 25 years. The patient never had adenopathy or other organ involvement. The radiographic findings were a mixture of sclerotic and lytic changes, an extremely rare and unusual presentation of the disease.

Female↗
PubMed2004

Intestinal pseudotumorous gouty nodulosis: a colonic tophus without manifestation of gouty arthritis.

A 37-year-old black woman with nephritis secondary to systemic lupus erythematosus, steroid-induced diabetes mellitus, and hypertension presented with fever, nausea, vomiting, and right upper quadrant abdominal pain with distension. Abdominal computed tomography (CT) scan revealed a colonic mass, and CT- guided fine-needle aspiration demonstrated birefringent crystalline material. After several weeks of antibiotic therapy, the patient underwent laparoscopic examination followed by extended right hemicolectomy for a large mass in the subserosa of the transverse colon. Pathological examination of this mass revealed it to be a gouty tophus. To our knowledge, no case of tophaceous gout presenting as an intestinal mass has previously been reported.

Adult↗
PubMed2004

Cystic degeneration of medullary bone infarction evaluated with magnetic resonance imaging correlated with pathologic examination.

OBJECTIVE: To evaluate the imaging pattern of cystic degeneration of medullary infarcts of the long bones. Medullary infarction of the long bones is a well-recognized entity. Cystic degeneration, however, is extremely rare and may frequently cause difficulty in the differential diagnosis. METHODS: We reviewed 15 cases of cystic degeneration of infarction of the long bones in 13 women and 2 men whose mean age was 41 (range 21-82) years. Conventional radiographs were obtained in every case. Eleven of the 15 cases were evaluated by magnetic resonance imaging (MRI). RESULTS: Six of the lesions occurred in the humerus, 5 in the femur, 2 in the tibia and 2 in the iliac bone. Fourteen patients presented with dull pain over the area; 1 patient was asymptomatic. The size of the lesions ranged between 1.5 cm and 12 cm in their greatest diameter. All of the 15 lesions proved to be benign on pathologic examination. On plain radiographs, about half of the lesions showed an expansile pattern and contained faint-to-dense calcifications. Using MRI, the lesions showed decreased signal intensity on T,-weighted imaging and appeared heterogeneously bright on T2-weighted imaging. After contrast injection, a well-defined unenhanced lesion was consistent with fluid collection. CONCLUSION: MRI is a valuable tool in diagnosing cystic degeneration of medullary infarction. Findings such as unenhanced lesions with well-defined margins are suggestive of fluid collection. The presence of dystrophic calcification and the thinned, but intact, cortex may suggest a benign underlying process such as medullary infarct.

Adult↗
PubMed2003

Solitary cysticercosis of the biceps brachii in a vegetarian: a rare and unusual pseudotumor.

We report a 40-year-old man with cysticercosis presenting as a solitary tumor in the biceps brachii muscle. Physical examination revealed an intramuscular mass and magnetic resonance imaging suggested a cyst. The histologic diagnosis was a cysticercus. Such solitary presentation of muscular cysticercosis is extremely rare with only a handful of sporadic reports in the literature.

Adult↗
PubMed2003

Anatomy of the posterior rotator interval: implications for cuff mobilization.

Release of the posterior rotator interval between the supraspinatus and infraspinatus tendons may be necessary to obtain appropriate mobilization for an anatomic rotator cuff repair. Ten cadaver shoulders were dissected to expose the region between the infraspinatus and supraspinatus from the spinoglenoid notch to the greater tuberosity. Measurements were made from the spinoglenoid notch to the glenoid rim, the glenoid rim to the confluence of the supraspinatus and infraspinatus musculotendinous junction, and from the confluence of the tendons to the insertion on the humerus. The histologic features of the posterior rotator interval were examined. The posterior rotator interval is a clear structure, consisting of the glenohumeral capsule medially, which fuses with the supraspinatus and infraspinatus tendons laterally. The average length of the posterior rotator interval was 77.8 mm which includes the distance from the spinoglenoid notch to the glenoid rim (25 mm; standard deviation, 2.89 mm; range, 21-28 mm), from the glenoid to the tendon confluence (25 mm; standard deviation, 1.95 mm; range, 21-28 mm), and from the tendon confluence to insertion (28 mm; standard deviation, 2.36 mm; range, 24-31 mm). Release of the posterior rotator interval can be important to realign the supraspinatus tendon if it is retracted and scarred at its posterior edge.

Arthroscopy↗
PubMed2003

Intraosseous epidermoid inclusion cyst in a great toe. A case report and review of the literature.

Epidermoid inclusion cysts are benign lesions that occasionally occur in the distal phalanges of the fingers but are less frequently identified and underreported in the toes. We describe a 55-year-old man with a history of work-related trauma followed by painful expansion of his right great toe, resulting in great anxiety. Imaging studies revealed a radiolucent lesion in the distal phalanx of his right hallux. Clinical differential diagnoses included the possibility of an intramedullary inclusion cyst and other various radiolucent lesions. During surgery, a cystic lesion that contained creamy material was discovered. Frozen section diagnosis of the lesion was an intraosseous epidermoid inclusion cyst. The lesion was removed and the patient recovered uneventfully. Although it has been reported that an unduly large number of phalangeal cysts have been treated by amputation, the judicious use of intraoperative frozen sections can prevent this scenario.

Bone Cysts↗
PubMed2002

Comparison of cathepsins K and S expression within the rheumatoid and osteoarthritic synovium.

OBJECTIVE: To determine and compare the expression of cathepsins K and S proteins in joints with rheumatoid arthritis (RA) and osteoarthritis (OA) and to determine the effect of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) on the expression of cathepsin K in fibroblast-like synoviocytes. METHOD: Expression and localization of cathepsins K and S were determined by immunohistochemistry in the synovium of 10 RA- and 8 OA-affected joints. Northern and Western blot analyses were performed to analyze cathepsin K and S expression in primary fibroblast-like synoviocyte cultures from RA and OA patients. The effect of IL-1 beta and TNF alpha on the expression and secretion of cathepsin K in primary cultures of synoviocytes was determined by real-time polymerase chain reaction and Western blot analysis. Staining of in situ activity was used to identify active cathepsin K enzyme in primary synovial fibroblast cultures. RESULTS: Cathepsin K and S protein expression was identified in the synovium from patients with RA and OA. Cathepsin K protein was localized in synovial fibroblasts, stromal multinucleated giant cells, and, to a lesser degree, in CD68+ macrophage-like synoviocytes. Of note is the expression of cathepsin K in synovial fibroblasts and mononuclear macrophage-like cells at sites of cartilage erosion in RA and in interdigitating cells of lymphocyte-rich areas. In contrast, cathepsin S expression was restricted to CD68+ macrophage-like synoviocytes, interdigitating cells, and endothelial cells of blood vessels. Cathepsin K protein expression in the interstitial areas and perivascular regions of RA-derived synovial specimens was 2-5 times higher than in OA samples (P < 0.001), whereas the expression of cathepsin S did not significantly differ in these diseases. Cathepsin K expression levels in normal synovium were low and restricted to fibroblast-like cells. Of note, cathepsin K also was expressed in repairing fibrocartilage in 1 OA specimen. Primary cell cultures of RA- and OA-derived synovial fibroblasts expressed comparable amounts of cathepsin K at the transcript and protein levels. Both cell cultures secreted mature cathepsin K as well as procathepsin K, and expressed active cathepsin K in cytosolic vesicles. In contrast, neither RA- nor OA-derived fibroblasts expressed detectable levels of cathepsin S. IL-1 beta and TNF alpha stimulated the transcript (7-8-fold) and protein expression (2-fold) of cathepsin K (P < 0.05) in primary synovial fibroblast cultures, without differences in expression between RA- and OA-derived synovial fibroblasts. CONCLUSION: The presence of cathepsin K polypeptide in synovial fibroblasts and macrophage-like cells in normal, OA, and RA synovia suggests a constitutive expression of this protease and a role in synovial remodeling. The comparable increase in cathepsin K expression after stimulation of RA- and OA-derived synovial fibroblasts with IL-1 beta and TNF alpha further suggests that the expression of cathepsin K is independent of cellular alterations leading to the invasive phenotype of RA-synovial fibroblasts. However, the overexpression of cathepsin K in RA synovia due to an increase in the number of cathepsin K-expressing cells identifies this enzyme as a candidate protease for the pathologic degradation of articular cartilage. Cathepsin S expression in macrophage-like synoviocytes suggests dual activity in antigen presentation and matrix degradation in the inflamed synovia.

Arthritis, Rheumatoid↗
PubMed2002

Coexistence of primary bone tumours: report of 4 cases of collision tumours.

OBJECTIVE: To report, in 4 patients, the occurrence of 2 different primary tumours in proximity in the same bone. Three patients had osteosarcomas, and 1 had a giant cell tumour; all had coincident metaphyseal fibrous defect. METHODS: Four patients (2 women, 1 man and 1 boy; 18, 25, 24 and 10 years of age, respectively) presented with progressive pain in the knee and distal thigh. All were studied by radiography, magnetic resonance imaging was done in 3 patients, and diagnostic open biopsy was performed for all. RESULTS: Radiologic studies demonstrated tumours in the distal end of the femur in all 4 patients. Biopsy tissue showed a metaphyseal fibrous defect in all, with coexistence of an associated giant cell tumour in 1 patient and an osteosarcoma in each of the others. In all cases, the metaphyseal fibrous defect was penetrated by the adjacent tumour. CONCLUSIONS: Despite the relative prevalence of metaphyseal fibrous defect, giant cell tumour and osteosarcomas in the distal end of the femur and their occurrence in approximately the same age group, their association has rarely been reported. As both giant cell tumours and osteosarcomas are usually diagnosed late in their clinical course, they may outgrow and destroy any evidence of pre-existing metaphyseal fibrous defect. The rate of destruction is also influenced by the distance between the 2 lesions--the shorter the distance, the earlier the destruction.

Adolescent↗
PubMedDate not supplied

Primary pulmonary artery leiomyosarcoma.

Primary pulmonary artery sarcomas are uncommon neoplasms with up to 20% of cases being leiomyosarcomas. In many instances, the diagnosis is difficult and delayed. We report the case of a 75-year-old male who presented with symptoms suggestive of recurrent pulmonary thromboemboli, in which a primary leiomyosarcoma of the pulmonary artery was successfully removed surgically. Three years after surgery, the patient is well and with no evidence of recurrence or metastatic disease.

Aged↗