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Biomedical subjects

K Krishnan Unni

Publications and source records attributed to K Krishnan Unni.

At least 19 recordsLinked to original sources
PubMed2006

Periosteal osteoblastoma: report of a case with a rare histopathologic presentation and review of the literature.

Osteoblastoma is an uncommon benign bone tumor most commonly located in the vertebral column or metaphysis of a long bone. Periosteal location is rare. We report a periosteal-based osteoblastoma, arising from the proximal tibia, in a 20-year-old woman who presented with knee swelling and pain of 2-year duration. Imaging studies showed a metaphyseal surface-based lesion with patchy radiodensities. The cortico-medullary junction was intact. The lesion was totally excised. Histopathologic evaluation disclosed immature bone and osteoid deposition in a vascularized stroma, associated with numerous osteoblasts and osteoclasts rimming the bony trabeculae. Plate-like arrangements of cartilage in the margin of the neoplastic tissue were also identified. At 16 months postoperatively, the patient was well without recurrence. Although extremely unusual, the presence of cartilage does not necessarily exclude the diagnosis of osteoblastoma.

Adult↗
PubMed2006

Follow-up study of long-term survivors of osteosarcoma in the prechemotherapy era.

Osteosarcoma is the most common primary bone sarcoma. Several studies published in the 1960s established that approximately one fifth of patients survive when treated with surgery alone. There is no information, however, about the long-term consequences of osteosarcoma. It is especially relevant to know if these patients are at risk for a second malignancy. We reviewed all clinical records from long-term (defined as more than 10 years) osteosarcoma survivors treated at Mayo Clinic in the prechemotherapeutic era from 1900 to 1960. We re-reviewed histological sections for most cases. Patients or next of kin provided follow-up information during telephone interviews. Rates of second malignancy were compared with expected rates in the population at large. We identified 465 patients treated for osteosarcoma. Of these patients, 83 (17.8%) were long-term survivors, including 19 who were alive up to 65 years after treatment. Of the 7 patients with pulmonary metastases, 3 died. A second malignancy developed in 26 patients, 15 of whom died of the malignancy. Although long-term survivors of osteosarcoma have a higher incidence of a second malignant tumor than a normal population, this increase was not statistically significant. No demographic or histological variables predicted long-term survival.

Age Distribution↗
PubMed2006

Intraabdominal myositis ossificans: a report of 9 new cases.

Intraabdominal myositis ossificans (IMO) is a rare benign disorder characterized by reactive bone formation in intraabdominal soft tissue that should be distinguished from a malignant condition. We retrospectively searched our patient records and report 9 new cases of IMO. The lesions occurred in 7 men and 2 women with a mean age of 50 years (range, 24--76 years), 5 of whom had previous abdominal surgery. Histologically, all the cases were similar, consisting of a reactive mesenchymal process in adipose tissue. Mitosis was observed, but with no atypical forms, and the lesions lacked malignant cytologic features. IMO is an uncommon benign lesion that develops relatively rapidly. The pathogenesis is related to intraabdominal surgical procedures, but the exact mechanism remains to be determined.

Adult↗
PubMed2004

Primary Ewing's sarcoma of the vertebral column.

OBJECTIVE: To determine the demographics, imaging findings, clinical symptoms, and prognosis of primary vertebral Ewing's sarcoma (PVES). DESIGN: A retrospective review of medical records and radiological studies of patients diagnosed with PVES from 1936 through 2001 in our institution and Department of Pathology consultation files was undertaken. Metastatic and soft tissue Ewing's sarcoma cases were excluded. RESULTS: From a total of 1,277 cases of Ewing's sarcoma, 125 (9.8%) had a primary vertebral origin. There were 48 females and 76 males. Patient ages ranged from 4 to 54 (mean 19.3, standard deviation 10.7, median 16) years. Vertebral column distribution was four cervical (3.2%), 13 thoracic (10.5%), 31 lumbar (25%), and 67 sacrum (53.2%). More than one vertebral segment was involved in ten cases (8%). Satisfactory imaging studies were available in 51 patients: 49 radiographs, 27 computerized tomography (CT), and 23 magnetic resonance imaging (MRI) studies. The majority of tumors were lytic (93%). Three cases were mixed lytic and sclerotic (6%) and one sclerotic. In the nonsacral spine, the majority of lesions (12/20) involved the posterior elements with extension into the vertebral body. Five cases were centered in the vertebral body with extension into the posterior elements. Two cases were limited to the posterior elements, and one case solely involved the vertebral body. Ala was the most frequently affected site in the sacrum (18/26). Spinal canal invasion was frequent (91%). Detailed clinical information was available in 53 patients. Duration of symptoms ranged from 1 to 30 (mean 7) months. Local pain was the first symptom and seen in all cases. Neurological deficits were present in 21 (40%) cases. All patients received radiation in various dosages; 70% additionally received chemotherapy. Twenty-five patients had surgery, and two patients received bone marrow transplantation. Forty-five patients had follow-up; the five-year disease-free survival probability is 0.53. Disease-free survival probabilities are 0.60 for sacral tumors and 0.45 for nonsacral tumors. CONCLUSION: PVES is an uncommon tumor, usually seen in the second decade of life (mean age 19.3 years) with a male predilection (62%). An aggressive osteolytic lesion, particularly in the sacrum, should raise suspicion for this tumor in adolescents. Prognosis was similar in sacral and nonsacral tumors.

Adolescent↗
PubMed2004

Imaging features of low-grade central osteosarcoma of the long bones and pelvis.

PURPOSE: To determine the age and gender distribution and imaging features of low-grade central osteosarcoma (LGCOS) of the long bones and pelvis and to discuss our findings in the context of lesions for which LGCOS has been mistaken. MATERIALS AND METHODS: We reviewed 99 cases of LGCOS collected between 1919 and 2002 from our institution and pathology consultation files. Adequate imaging was available in 70 cases (36 radiographs only, 17 radiographs/CT, 12 radiographs/MRI, 2 radiographs/CT/MRI, 2 CT only, 1 MRI only, 5 bone scans). RESULTS: Patient average age was 30.1+/-14.2 years, with a slight female predominance. The femur and tibia were the most common long bones involved (29 and 20 each) with the majority of these tumors arising around the knee, followed by the fibula, radius, humerus and ulna (four, three, two and one case each). Flat bones were involved in six cases (three pelvis, one rib, two scapulae). Short tubular bones were involved in five cases (two metatarsal, two phalanges, one clavicle). The lesion extended to the end of the affected long bone in 22 of 59 cases. Lesions were large at presentation (mean 7.9+/-4.6 cm, range 2-24). Four radiographic patterns were identified: lytic with varying amounts of thick and coarse trabeculation ( n=22), predominantly lytic with few thin, incomplete trabecula ( n=21), densely sclerotic ( n=17) and mixed lytic and sclerotic ( n=10). Lesions were benign-appearing overall with focally aggressive features. CT or MRI demonstrated cortical breech or extension into the soft tissues in all cases. CONCLUSIONS: LGCOS has a variable appearance on radiographs. A frequent pattern is a slow-growing large intracompartmental fibro-osseous lesion with varying amounts of septal ossification associated with focal areas of aggression. A homogeneously sclerotic pattern was also noted. Imaging with CT or MRI was helpful in every instance in our series in identifying areas of soft tissue extension or cortical disruption suggestive of a low-grade malignancy.

Adult↗
PubMed2004

Primary vertebral osteosarcoma: imaging findings.

PURPOSE: To evaluate patient age and sex and location and imaging appearances of primary vertebral osteosarcoma (PVOS) compared with histologic subtypes. MATERIALS AND METHODS: Retrospective review (1915-2001) of imaging findings in patients with histologically proved primary osteosarcoma of vertebral column was performed. Two radiologists in consensus reviewed findings for location, origin site, matrix pattern, and spinal canal invasion and compared them with histologic subtypes. Radiation-induced, Paget, metastatic, and multifocal osteosarcoma were excluded. RESULTS: Of 4,887 osteosarcoma cases, 198 (4%) were PVOS arising from vertebral column. There were 103 female and 95 male patients (age range, 8-80 years; median age, 34.5 years). Involvement included cervical (27 patients), thoracic (66 patients), lumbar (64 patients), and sacral (41 patients) spine. Adequate imaging findings were available in 69 patients, and involvement of two levels was seen in 12 (17%). In nonsacral spine, most tumors (44 cases) arose from posterior elements, with partial involvement of vertebral body. Lesions confined to vertebral body were less frequent (12 cases). Sacral tumors involved body and sacral ala. The most common histologic subtypes were osteoblastic (47 patients), chondroblastic (12 patients), telangiectatic (four patients), fibroblastic (four patients), small cell (one patient), and epithelioid (one patient). The majority (55 cases) demonstrated osteoid matrix mineralization; 17 showed marked mineralization. Five cases with marked mineralization were confined to vertebral body, with "ivory vertebra" appearance. Purely lytic pattern was seen in 14 (20%) cases. Lytic pattern was seen in four (100%) telangiectatic, three (75%) fibroblastic, three (25%) chondroblastic, three (6%) conventional osteoblastic, and one (100%) small-cell subtypes. Invasion of spinal canal was common (84% of cases). Appearance simulating osteoblastoma without soft-tissue mass was present (seven cases). Pathologic compression fractures were identified (seven patients). CONCLUSION: This study provides age and sex distribution and location and imaging features in a large series of PVOS.

Adolescent↗
PubMed2004

Absence of amplification of HER-2/neu (c-erbB-2) gene in Ewing's sarcoma: a real-time polymerase chain reaction method.

Amplification and overexpression of the HER-2/neu (c-erbB-2) oncogene have been observed in many cancers and are associated with a poor prognosis particularly in breast cancer. The human epidermal growth factor (HER)-2 receptor has recently been implicated in Ewing's sarcoma tumor cell line growth and chemosensitivity. The present study evaluates the amplification of HER-2/neu gene in paraffin sections from 42 cases of Ewing's sarcoma by a real-time quantitative polymerase reaction method using LightCycler system (Roche diagnostics, GmbH Mannheim, Germany). The relative copy number of HER-2/neu versus beta-globin was calculated at the crossing point. The mean calculated copy number in these cases of Ewing's sarcoma and normal controls was 26.43 and 26.93, respectively. The p value was 0.215 (p<0.05). Our results demonstrated an absence of HER-2/neu oncogene amplification in Ewing's sarcomas, and we suggest that HER-2/neu is not a biologically or therapeutically important pathway in Ewing's sarcoma.

Beta-Globulins↗
PubMed2003

Myeloma of the jaw bones: a clinicopathologic study of 33 cases.

BACKGROUND: A clinicopathologic study of 33 cases of plasma cell neoplasm of the jaw bones was performed. METHODS: The Mayo Clinic's pathology files through 1995 were reviewed for cases of plasma cell neoplasia involving the jaw bones. Clinical data, radiologic features, and follow-up data were obtained from the hospitals of origin, referring physicians, and Mayo Clinic files. The histopathologic features of the 33 tumors were studied. RESULTS: There were 21 (64%) male and 12 (36%) female patients, ranging in age from 25 to 81 years (mean, 57.7 years). Twenty-one tumors (64%) were classified as solitary plasmacytoma of bone (SPB) and 12 (36%) as multiple myeloma (MM). Among the SPB cases, 15 (71%) involved the maxilla, and 14 patients were men, with a mean age of 57.1 years. Abnormal serum protein was found in 22% of patients, and in nine patients (43%) the SPB converted to MM after a median of 20.7 months. Among the MM cases, seven (58%) affected the maxilla, seven patients were men with mean age of 58.3 years, and abnormal serum protein and Bence-Jones protein were found in 42% and 73% of the patients, respectively. Anaplastic histology was identified in seven (33%) SPB and six (50%) MM tumors, and amyloid was present in eight (38%) SPB and three (25%) MM tumors. Twelve (57%) SPB patients died of the disease after a median disease-free survival of 6.75 years, and the overall and disease-free survival rates at 5 and 10 years were 52%, 33%, 33%, and 24%, respectively. All MM patients died of the disease after a median survival of 17.6 months, and the 5-year and 10-year survival rates were 8% and zero. Eighty-six percent of the SPB patients with anaplastic histologic findings died of the disease (average survival, 3.8 years), whereas only 43% of those with classic histologic findings died of the disease (average survival, 11.75 years). Among MM patients, anaplastic histologic findings were associated with a 9-month average survival (26-month average survival for MM patients with classic histologic findings). CONCLUSIONS: SPB patients seem to have a better prognosis than MM patients, and 43% of SPB tumors convert to MM after an average of 20.7 months. Anaplastic histologic findings seem to be associated with lower survival rates and periods for SPB patients and lower survival periods for MM patients.

Adult↗
PubMed2003

Secondary chondrosarcoma in osteochondroma: report of 107 patients.

Secondary chondrosarcomas are rare; recognition and diagnosis are difficult. Slow growth and late recurrence require long-term followup to understand the clinical course. In the current study, 107 patients had secondary chondrosarcoma arising in a solitary osteochondroma (61 patients) or multiple exostoses (46 patients). All histologic slides were reviewed without knowledge of the outcome, and radiologic studies were available for review in 71 cases. Patients with secondary chondrosarcoma were one to two decades younger than those with primary chondrosarcoma. Male preponderance and a predilection for flat bones were observed. The radiologic signs of sarcomatous degeneration included irregularity of the margin, inhomogeneous mineralization, and an associated soft tissue mass. The tumors generally were well-differentiated. Only 10 tumors were classified as Grade 2. Five-year and 10-year local recurrence rates were 15.9% and 17.5%, respectively, and 5- and 10-year mortality rates were 1.6% and 4.8% for patients having initial treatment at the authors' institution. Metastasis developed in five patients: in the lung in four patients and in the groin region in one patient. Most patients who died of tumor died of local recurrence. Wide excision had the lowest local recurrence rate. With successful surgical treatment, patients may have long-term disease-free survival.

Adolescent↗
PubMed2003

Solid variant of aneurysmal bone cysts in long tubular bones: giant cell reparative granuloma.

OBJECTIVE: The purpose of this study was to determine the age distribution, location, and imaging features of histologically proven solid variants of aneurysmal bone cysts in long tubular bones. MATERIALS AND METHODS: We performed a retrospective review of imaging studies of histologically proven solid aneurysmal bone cysts in long bones between 1961 and 2001. There were 30 cases comprising 29 radiographic, six CT, and eight MR imaging examinations. The lesions were evaluated for bone involved, location within a long bone, matrix, size, soft-tissue mass, and MR imaging characteristics. The imaging findings were correlated with the histologic findings. RESULTS: The patients were 17 females and 13 males ranging in age from 2 to 58 years (mean, 18 years). The bones involved were the femur (n = 10), the ulna (n = 7), the tibia (n = 7), the humerus (n = 2), the radius (n = 2), and the fibula (n = 2). The lesions were five juxtaarticular, 13 metaphyseal, one diametaphyseal, and 11 diaphyseal. The location was eccentric in 20 cases, of which two were intracortical and two periosteal, and central in 10. Lesion size varied between 1 and 7 cm. Thirty-three percent of lesions were nonaneurysmal. Four lesions were mineralized. A soft-tissue mass was present in four cases. Four lesions showed a permeative-lytic pattern simulating a malignant process. Unusual findings included periosteal reaction and development of a solid aneurysmal bone cyst in a preexisting fracture. MR imaging showed solid elements in all cases and pronounced edema in 50% of cases. CONCLUSION: Solid aneurysmal bone cyst is a reactive nonneoplastic bone lesion with varied imaging characteristics; one third of lesions are nonaneurysmal.

Adolescent↗
PubMed2002

Vertebral chondroblastoma.

OBJECTIVE: To determine the age distribution, gender, incidence, and imaging findings of vertebral chondroblastoma, and to compare our series with findings from case reports in the world literature. DESIGN AND PATIENTS: Case records and imaging findings of nine histologically documented vertebral chondroblastomas were retrospectively reviewed for patient age, gender, vertebral column location and level, morphology, matrix, edema, soft tissue mass, spinal canal invasion, and metastases. Our findings were compared with a total of nine patients identified from previous publications in the world literature. The histologic findings in our cases was re-reviewed for diagnosis and specifically for features of calcification and secondary aneurysmal bone cyst (ABC). Clinical follow-up was requested from referring institutions. RESULTS: Nine of 856 chondroblastomas arose in vertebrae (incidence 1.4%; thoracic 5, lumbar 1, cervical 2, sacral 1). There were six males and three females ranging in age from 5 to 41 years (mean 28 years). Satisfactory imaging from seven patients revealed the tumor to arise from the posterior elements in four and the body in three. All tumors were expansive, six of seven were aggressive, and the spinal canal was significantly narrowed by bone or soft tissue mass in six. In one patient canal invasion was minimal. Calcification was pronounced in two and subtle in four. The sole nonaggressive-appearing tumor was heavily mineralized. Bony edema and secondary ABC were not seen on MR imaging. None of the cases had microscopic features of significant secondary ABC. Calcification, and specifically "chicken wire" calcification, was identified in two patients. Pulmonary metastases occurred in none. CONCLUSIONS: Vertebral chondroblastoma is a rare neoplasm that presents later in life than its appendicular counterpart. On imaging it is aggressive in appearance with bone destruction, soft tissue mass, and spinal canal invasion. The lesions contain variable amounts of mineral. Secondary aneurysmal cyst bone formation was not a feature in our study group.

Adolescent↗
PubMed2002

Translocation der(13;21)(q10;q10) in skeletal and extraskeletal mesenchymal chondrosarcoma.

Cytogenetic studies of mesenchymal chondrosarcoma are few and to date, no specific or recurrent aberrations have been found. In this investigation, the cytogenetic and molecular cytogenetic (spectral karyotypic and fluorescence in situ hybridization) findings for two mesenchymal chondrosarcomas, one arising skeletally and the other extraskeletally, are reported. An identical Robertsonian translocation involving chromosomes 13 and 21 [der(13;21)(q10;q10)] was detected in both cases, possibly representing a characteristic rearrangement for this histopathologic entity. Both cases also exhibited loss of all or a portion of chromosomes 8 and 20 and gain of all or a portion of chromosome 12. The observation of similar chromosomal abnormalities in both skeletal and extraskeletal mesenchymal chondrosarcoma supports a genetic as well as histopathologic relationship between these anatomically distinct neoplasms.

Adult↗
PubMed2002

The rate of false-positive results with EUS-guided fine-needle aspiration.

BACKGROUND: The aims of this study were to determine the rate of false-positive diagnosis with EUS-guided fine-needle aspiration and to identify factors contributing to this type of error. METHODS: The records of 577 patients undergoing EUS-guided fine-needle aspiration were reviewed and a subset of 188 patients with malignant cytology who underwent surgery was identified. Operative histopathology was compared with EUS-guided fine-needle aspiration cytopathology and false-positive cases were identified. An experienced cytopathologist, who was not involved with the original interpretation of the specimens, reviewed these cases to identify any factor(s) contributing to the errors. RESULTS: Three cases of false-positive diagnosis were identified (1.6%; 95% CI [0.3%, 4.6%]). By aspiration site, the false-positive rates were as follows: pancreas 2/39 (5.1%), 95% CI [0.6%, 17.3%]; lymph nodes 1/136 (0.7%), 95% CI [0.02%, 4.0%]; and other sites 0/13, 95% CI [0.0%, 24.7%]. In both instances of a false-positive diagnosis for a pancreatic aspiration cytologic specimen, interpretative errors were identified. The false-positive interpretation of cytologic material aspirated from a lymph node occurred in a patient without any evidence for malignancy at surgery. In 111 patients with confirmed esophageal, gastric, or rectal malignancy undergoing EUS-guided fine-needle aspiration of nonperitumoral lymph nodes, there was no false-positive diagnosis, suggesting that specimen contamination by luminal tumor is rare. CONCLUSION: The overall rate of false-positive diagnosis for EUS-guided fine-needle aspiration is similar to that reported for other modalities. Most false-positive diagnoses are caused by interpretation errors.

Biopsy, Needle↗
PubMed2002

Lack of Bcl10 mutations in malignant cartilaginous tumors.

The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas. Somatic mutations of Bcl10 were found in not only t(1;14)-bearing MALT lymphomas, but also a wide range of other tumors. To clarify the actual frequency and spectrum of Bcl10 mutations in primary malignant chondrogenic tumors, we examined 89 cases of malignant chondrogenic tumors comprising 17 conventional chondrosarcomas, 33 mesenchymal chondrosarcomas, and 39 clear cell chondrosarcomas. Polymerase chain reaction single-stranded conformation polymorphism and sequencing analyses were done. No Bcl10 mutations were found in our series of malignant chondrogenic tumors. While screening for mutations, we also found three polymorphisms at codons 8 exon 1 of the Bcl10 gene. Our results strongly suggest that somatic mutations of Bcl10 are extremely rare in malignant cartilaginous tumors and do not commonly contribute to their molecular pathogenesis.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Clinicopathologic features, diagnosis, and treatment of fibrosarcoma of bone.

Fibrosarcoma of bone is a relatively rare tumor; it accounts for less than 5% of bone sarcomas. The anatomical sites most commonly involved are the metaphyses of long tubular bones. Local pain, swelling, limitation of motion, and pathologic fracture are the common clinical signs and symptoms. Typical imaging findings include eccentrically located lytic lesions, with a geographic, moth-eaten, or permeative pattern of bone destruction, and extension into adjacent soft tissues. Surgery is the treatment of choice. The type of surgical procedure depends mainly on histologic grade, local conditions, and tumor location. With a high probability of metastases (>70%) after surgical treatment, perioperative adjuvant treatment modalities should be considered for high-grade tumors. The most important prognostic factors affecting survival include tumor grade, patient's age, and tumor location.

Bone Neoplasms↗