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Biomedical subjects

A K Karak

Publications and source records attributed to A K Karak.

At least 19 recordsLinked to original sources
PubMed2001

Papillary carcinoma of the thyroid and its variants: a cytohistological correlation.

Fine-needle aspiration cytology (FNAC) is considered highly specific for the diagnosis of papillary carcinoma of the thyroid (PCT). In recent years, several variants of PCT have been described. An attempt was made to gauge the accuracy of classification of variants of PCT on aspirates. Cytology smears from 124 of 150 cases of histologically proven PCT with a prior FNAC were reviewed over a 16-yr period. A diagnosis of papillary carcinoma on FNAC was made in 93 cases. Further subclassification of these cases was done on cytology and tissue sections independently. The variants of PCT classified on FNAC were classical PCT (PCT-CL), 76 cases; Hurthle-cell variant (PCT-HCV), 3 cases; follicular variant (PCT-FV), 6 cases; tall-cell variant (PCT-TCV), 2 cases; high-grade variant (PCT-HG), 2 cases; and 2 cases each which were debatably PCT-CL/PCT-FV and PCT-CL/PCT-HG. Cytology typing was accurate in 65 of the 72 classical variants, while only 7 of the 22 follicular variants were correctly identified on cytology. Two of the 3 high-grade papillary carcinomas (PCT-HG) were identified on FNAC, and the solitary case of tall-cell variant could readily be classified on cytology. In conclusion, identification of the various variants of PCT is possible, though difficulty is encountered in correctly categorizing the follicular variant, which is often mistaken for a follicular neoplasm. Also, identification of the solid variant and the papillary carcinoma with nodular fasciitis-like stroma was a problem on cytology. Another interesting observation in our series is that an admixture of various cell types was seen in the smears and corroborated on histology to be present in focal areas.

Biopsy, Needle↗
PubMed2001

Evaluation of diagnostic efficiency of computerized image analysis based quantitative nuclear parameters in papillary and follicular thyroid tumors using paraffin-embedded tissue sections.

Computerized image analysis (IA) system has emerged in recent years as a very powerful tool for objective and reproducible quantification of histological features. It has shown considerable potential for diagnostic application in diverse histological situations. The objectives of the present study were to evaluate the discriminatory diagnostic efficiency of computerized image analysis based quantitative subvisual nuclear parameters in papillary and follicular neoplasms of thyroid. A total of 60 cases were studied. Forty-four cases belonged to training set and 16 cases belonged to a test set. A minimum of 100 nuclei was analyzed in each case using uniform 5 m mm thick hematoxylin stained sections. The IA workstation comprised of an Olympus microscope, a 10 bit digital video camera, an image grabber card and a pentium 120 MHz computer. Optimas 5.2 software was utilized for data collection on 8 morphometric and 8 densitometric parameters. Multivariate stepwise discriminant statistical analysis of data was done with the help of BMDP statistical software release 7.0. Results from a training set revealed correct classification rates of 98.0%, 84.5% and 61.2% for the histological groups of hyperplastic papillae versus papillae of papillary carcinoma (group I), follicular variant of papillary carcinoma versus the broad category of follicular neoplasms consisting of both follicular adenoma and follicular carcinoma (group II) and follicular adenoma versus follicular carcinoma (group III), respectively. Results of test set revealed correct classification rates of 100%, 80% and 50% for groups I, II and III respectively. It was concluded that computerized nuclear IA parameters have potential usefulness for discriminating benign versus malignant papillary lesions of thyroid, follicular variant of papillary carcinoma versus follicular adenoma and/or follicular carcinoma but are of no value in discriminating between follicular adenoma and follicular carcinoma.

Adenocarcinoma, Follicular↗
PubMed2001

Laryngeal myxoma.

Myxoma is an uncommon neoplasm in the head and neck region. Laryngeal myxomas are rarer still. We report a case of a large myxoma in the supraglottis, that was excised endoscopically.

Humans↗
PubMed2000

A comparative survival evaluation and assessment of interclassification concordance in adult supratentorial astrocytic tumors.

Classification and grading of astrocytic tumors has been the subject of several controversies and no universally accepted classification system is yet available. Nevertheless, acceptance of a common system is important for assessing prognosis as well as easy comparative evaluation and interpretation of the results of multi-center therapeutic trials. We report the results of a single center study on comparative survival evaluation along with assessment of inter-classification concordance in 102 cases of supratentorial astrocytic tumors in adults ((3) (3)16 years of age). Hematoxylin and eosin (H&E) stained slides of these 102 cases were reviewed independently by two pathologists and each case classified or graded according to four different classification systems viz. Kernohan, Daumas-Duport (SAM-A), TESTAST-268 and WHO. The histological grading was then correlated with the survival curves as estimated by the Kaplan-Meier method. The most important observation was that similar survival curves were obtained for any one grade of tumor by all the four classification systems. Fifty three of the 102 cases (51.9%) showed absolute grading concordance using all 4 classifications with maximum concordant cases belonging to grades 2 and 4. Intra-classification grade-wise survival analysis revealed a statistically significant difference between grade 2 and grades 3 or 4, but no difference between grades 3 and 4 in any of the classification systems. It is apparent from the results of this study that if specified criteria related to any of the classification systems is rigorously adhered to, it will produce comparable results. Hence, preferential adoption of any one classification system in practice will be guided by the relative ease of histologic feature value evaluation with maximum possible objectivity and reproducibility. We recommend the Daumas-Duport (SAM-A) system since it appears to be the simplest, most objectivized for practical application and highly reproducible with relative ease.

Adolescent↗
PubMed2000

Hashimoto's thyroiditis: countrywide screening of goitrous healthy young girls in postiodization phase in India.

Countrywide salt iodization, to prevent nutritional iodine deficiency, has been achieved in India recently. The current study was planned to evaluate the prevalence of goiter and thyroid autoimmunity and assess thyroid functional status in a cohort of 6283 healthy schoolgirls from different parts of the country in the postiodization phase. Goitrous girls (n = 1810; 28% of subjects) were investigated for serum T4 and TSH, antithyroid microsomal antibody (TMA) and antithyroglobulin antibody (TGA), urinary iodine excretion, and cytomorphology by fine-needle aspiration cytology (FNAC). FNAC carried out successfully in 764 goitrous girls revealed juvenile autoimmune thyroiditis (JAT) in 58 (7.5%), which included Hashimoto's thyroiditis in 43 (5.6%) and focal lymphocytic thyroiditis in 15 (1.9%). TMA and TGA estimated in 722 goitrous girls detected significantly positive titers of TMA (> or =1:1600) and TGA (> or =1:160) in 52 (7.2%) and 4 (0.55%) girls, respectively. Only 29 (67.4%) girls with Hashimoto's thyroiditis were TMA positive. In patients with FNAC-proven JAT, overt clinical and biochemical hypothyroidism was seen in three (6.5%) and subclinical hypothyroidism in seven (15%). Subclinical hyperthyroidism was detected in 5.1% cases of JAT, and none had overt hyperthyroidism. No definite correlation was seen between urinary iodine excretion and thyroid autoimmunity.

Adolescent↗
PubMed1999

Pituitary adenoma with neuronal choristoma: a report of two rare cases.

Two rare cases of pituitary adenoma with neuronal choristoma are described. Both patients were female and presented with features of acromegaly with elevated growth hormone and prolactin levels. Radiologically, both lesions were predominantly intrasellar in location with extension into suprasellar region, but hypothalamus was not involved. Histopathological examination revealed a mixture of chromophobe pituitary adenoma cells and neuronal cells. In both cases, the adenoma component was positive for growth hormone and prolactin. Interestingly, immunopositivity for alpha-subunit, cytokeratin and prolactin was seen in the adenoma and neuronal cells in one case. Our findings support the hypothesis that the neuronal cells possibly arise from adenoma cells as a result of metaplasia.

Acromegaly↗
PubMed1999

A correlative study of gliomas using in vivo bromodeoxyuridine labeling index and computer-aided malignancy grading.

An in vivo bromodeoxyuridine (BrdU) labeling index (LI) was estimated in 43 cases of astrocytic tumors and mixed gliomas by one hour intra-operative intravenous infusion at a dose of 200 mg/m2 and correlated with (a) histological grading using a computer aided malignancy classifier TESTAST-268; and (b) histological typing using WHO classification. The lowest BrdU LI was seen in pilocytic and gemistocytic astrocytomas followed by astrocytomas, anaplastic astrocytomas and glioblastoma multiforme in that order. Mixed oligoastrocytomas followed the pattern of their astrocytic counterparts. Tumors of similar histological type showed different BrdU LI values especially amongst astrocytomas and glioblastomas. A statistically significant difference in the BrdU LI was also noted between the higher TESTAST grades of astrocytomas (T III and IV) versus the lower TESTAST grades (T II). Unlike earlier reports in literature, in the present study the category of BrdU LI of <1 contained no case of anaplastic astrocytoma or glioblastoma multiforme (TESTAST grades III and IV). Likewise, the category of BrdU LI >5 contained only anaplastic astrocytoma and glioblastoma multiforme (TESTAST grades III and IV). Maximum spread of cases was seen in the BrdU LI category of 1-5, not only in terms of histological types but also TESTAST grades. Thus there appeared to be a positive trend of increasing BrdU LI values both with histological types and increasing TESTAST grades. Further, an interesting observation was that by using a combination of TESTAST grades and BrdU LI, the histologically homogenous glioblastoma group could be further subdivided into 4 categories which showed a trend towards prognostic correlation. Thus, this study though preliminary with number of cases being small in some groups, highlights the possible usefulness of combined histological typing, TESTAST grading and in vivo BrdU LI for prognostication of gliomas especially glioblastoma multiforme.

Astrocytoma↗
PubMed1998

Fine-needle aspiration cytology in a case of isolated involvement of thyroid with Langerhans cell histiocytosis.

We present an unusual case of isolated thyroid involvement with Langerhans cell histiocytosis (LCH), diagnosed presumptively by fine-needle aspiration (FNA) cytology and subsequently confirmed by immunohistochemistry in a 13-yr-old boy. The cytologic findings include high cellularity in a hemorrhagic background, the presence of characteristic mononucleated and multinucleated Langerhans cells with prominent nuclear grooves, and abundant foamy cytoplasm in a background of mixed eosinophilic and aggregates of benign thyroid follicular cells. Further diagnostic confirmation was obtained by positive S-100 protein immunohistochemistry of the Langerhans histiocytes on paraffin-embedded sections of open thyroid biopsy of the prominently enlarged left lobe. We present the complete clinicopathologic features of this case, along with ultrasound, computerized axial tomographic, and technetium-99 scan findings. We also discuss possible differential diagnostic consideration in light of a review of the literature and the role of FNA cytologic diagnosis in such a rare yet cytomorphologically characteristic case.

Adolescent↗
PubMed1998

A study of proliferative markers in central neurocytoma.

To gain a better insight into the biological behavior of central neurocytomas, various proliferative indices were studied in these tumors and correlated with the histological features as well as the clinical outcome. Twenty cases of neurocytoma were selected over a 16 year period (1980-1995), which accounted for 0.28% of all intracranial tumors reported at this centre. Treatment consisted of surgical resection (total 14, subtotal six) followed by radiotherapy. Except for five patients who died of surgical complications, the remaining 15 were all alive and well during the follow-up period, varying from six months to 72 months (average 32 months). Thirteen tumors showed benign histological characteristics (Group I) while seven showed mitoses + necrosis (Group II). The proliferative index was assessed in formalin-fixed paraffin-embedded tissue of 17 cases using the silver nucleolar organiser region (AgNOR) technique and immunohistochemical staining for proliferating cell nuclear antigen (PCNA-PC10 antibody) and Ki-67 antigen (MIB-1 monoclonal antibody). The AgNOR counts ranged from 1.2 to 2.6 (mean 1.9 +/- 0.4), PCNA labeling index (LI) from 0.1 to 5.5 (mean 2.5 +/- 1.8) and MIB-1 LI from 0.1 to 3 (mean 0.8 +/- 0.02). There was no significant difference in any of these parameter values between histological Groups I and II, except that MIB-1 LI tended to be higher in Group II tumors. Further, there was no significant correlation between these proliferative indices and the mitotic rate of the tumors as well as the survival of the patients. A longer follow-up will be required to determine the relationship between proliferative markers and outcome as well as to bring out any heterogeneity in their biological behavior. Since these are relatively rare tumors, multicentric pooling of data will be required to reach a definitive consensus regarding their biological aggressiveness and consequentially, the use of radiotherapy in their treatment. The present report is a contribution in this direction.

Adolescent↗
PubMed1998

Assessment of proliferative potential of meningiomas using PCNA LI and AgNOR counts.

Seventy-six cases of international meningiomas were studied using staining for Proliferating Cell Nuclear Antigen (PCNA) and silver nucleolar organizer regions (AgNORs) in order to find out any correlation of these parameters to the histological typing of the tumours and their biological behaviour. Histologically, 35 of the 76 cases were benign, 12 atypical and 19 malignant. Ten cases were recurrent. A male preponderance with a male: female ratio of 1.6:1 was noted. Five of 76 cases were in children below 15 years of age. Majority of the tumours were convexity meningiomas. Overall PCNA labeling index (LI) values ranged from 0.1% to 11.0%. Benign group had an LI of 0.9 +/- 1.42 whereas atypical, malignant and recurrent group had LIs of 4.06 +/- 2.33, 2.91 +/- 2.66 and 3.36 +/- 3.76 respectively. One way analysis of variance test showed a significant difference in the distribution of LI between benign versus atypical, malignant and recurrent group (P < 0.05). A highly significant difference was also observed between PCNA LI of recurrent benign group versus non-recurrent benign group (p < 0.01, wilcoxon Rank Sum Test). On further classifying the tumours based on LI values, it was observed that 30 of 41 (73%) cases of combined atypical, malignant and recurrent group (i.e. biologically more aggressive group) had LI of > 1%, whereas 26 of 35 cases (74%) belonging to the benign group had LI of < 1%. Overall AgNOR counts ranged from 1.27 to 3.11. No statistically significant difference was found in AgNOR counts amongst the different groups of meningiomas. There was no correlation between PCNA LI and AgNOR counts. It was thus concluded that PCNA LI but not AgNOR counts in the primary tumour could be of potential value for more accurate assessment of biologic behaviour of meningiomas in conjunction with the conventional A histological parameters.

Adolescent↗
PubMed1998

Hyalinizing trabecular adenoma--a case report with FNAC histologic, MIB-1 proliferative index and immunohistochemical findings.

Hyalinizing trabecular adenoma is a recently described benign thyroid tumor, almost exclusively occurring in females. The morphological features of this entity overlap with both papillary and medullary carcinoma to varying extent. This, in turn, creates a situation of serious diagnostic pitfall particularly for a false positive diagnosis of papillary carcinoma in fine needle aspiration (FNA) cytology. False consideration of medullary carcinoma is also possible by the unwary especially if staining for Congo red and/or immunostaining for calcitonin is not resorted to. At histologic level, the distinctive architectural pattern is however of great help and thus poses a much lesser danger of misdiagnosis. We relate here our experience in a recently encountered case of hyalinizing trabecular adenoma and describe detailed FNA cytologic and histologic findings along with immunohistochemical profile using a panel of eight monoclonal antibodies. The tumor proliferative potential has also been assessed using MIB-1 (Ki-67) immunostaining. The various pros and cons of diagnostic pitfalls are discussed.

Adenoma↗
PubMed1997

MIB-1 proliferative index in parathyroid adenoma & hyperplasia.

A retrospective study on 22 cases of parathyroid adenoma, 9 cases of primary parathyroid hyperplasia and 14 specimens of normal suppressed glandular tissue was undertaken to determine the usefulness of proliferative index (PI) for discriminating adenoma from hyperplasia, as an adjunct to the existing histological criteria. PI was determined by avidin-biotin-complex immunostaining after high temperature microwave antigen retrieval in paraffin sections, using monoclonal MIB-1 antibody which detects paraffin resistant analogue of cell cycle-associated Ki-67 antigen. PI expressed as percentage positive cell nuclei, was 1.36 +/- 0.62 (range 0.04-2.72) in adenoma, 1.17 +/- 0.83 (0.02-1.98) in hyperplasia and 0.03 +/- 0.02 (0.00-0.06) in normal suppressed glandular tissue. While the difference between normal suppressed glandular tissue and adenoma and hyperplasia was significant (P < 0.001), that between adenoma and hyperplasia was not. We conclude that although PI could distinguish between normal suppressed glandular tissue versus glands with primary hyperparathyroidism, it failed as an additional useful parameter for discriminating between adenoma and hyperplasia, both of which have low but similar proliferative activity.

Adenoma↗
PubMed1996

A grading study of gliomas using computer aided malignancy classification and histologic morphometry.

Forty three cases of astrocytic tumors and mixed gliomas were studied with the aim of evaluating the reproducibility of the Kernohan grading system vis a vis (a) grading using computer-aided malignancy classifier TESTAST 268 and (b) grading by quantitative morphometric evaluation of the various histological parameters of TESTAST 268. These patients were then followed up for variable periods with a maximum of forty months. High inter and intra-observer variability were observed in the Kernohan grading system. TESTAST 268 was found to be simpler, rapid and more reproducible. However, one drawback observed of this system was that it did not completely eliminate inter-observer variability because there was still some subjectivity in assignment of the categorical values against the histological features. Morphometric evaluation of the semi-quantitative assignment values of the 4 histological variables in the TESTAST 268 classifier using Zeiss Morphomat-30 revealed a statistically significant difference between the clusters of the measured quantitative values. A repeat grading using TESTAST 268 and categorical assignment values of histological features derived from the absolute values obtained by morphometry resulted in complete elimination of inter-observer variability. Thus, this study highlights the importance of objectivisation using TESTAST 268 and histologic morphometry in the grading of gliomas. However, since this is a preliminary study on a small number of cases, no cut off values of these measurements have been proposed.

Adolescent↗
PubMed1996

Intracranial intraparenchymal schwannomas: a series of eight cases.

Intraparenchymal schwannomas of the CNS are extremely rare. Between 1979 and 1993 400 cases of intracranial schwannomas were operated on and among them were eight patients with intraparenchymal schwannomas comprising 2% of intracranial benign nerve sheath tumours. Four of them were located in the cerebral hemispheres and two each in the brain stem and in the cerebellum. In two cases, there was associated neurofibromatosis (NF-1 and NF-2, one case each). The age ranged from 6 months to 45 years with a male/female ratio of 3:1 and, surprisingly, six of them were in the left cerebral or cerebellar hemisphere.

Adolescent↗
PubMed1996

Basaloid-squamous carcinoma. A distinct histopathological entity.

Basaloid Squamous Carcinoma (BSC) is an uncommon aggressive neoplasm occurring in the upper aerodigestive tract. Lung as a primary site has only recently been reported. A combination of microscopic features is required to make a diagnosis and to differentiate it from other more common malignancies in these sites. Three cases of BSC including one in the lung are reported. There are no prior published reports of this neoplasms in Indian literature. The study highlights the typical microscopic features and the diagnostic difficulties which may be encountered.

Aged↗