Biomedical subjects
Publications and source records attributed to Rekha V Kumar.
Teratomas are tumors consisting of tissues derived from more than one germ cell line. Criteria for pulmonary origin are exclusion of a gonadal or other extra-gonadal primary site and origin entirely within the lung. Lung teratomas are rare, and for unknown reasons commonly involve the upper lobe of the left lung. We report a case of intrapulmonary teratoma in a 38-year-old male and review the relevant literature.
A 7-year-old boy with a positive history of vertical HIV transmission presented with a painful swelling over the left upper jaw of 20 days' duration. A provisional diagnosis of non-Hodgkin's lymphoma or embryonal rhabdomyosarcoma was made. Fine-needle aspiration cytology findings were inconclusive, and incisional biopsy tissue on routine stains gave an impression of small round cell tumor with plasmacytoid features. A series of histochemical stains and immunohistochemical studies was carried out to differentiate and characterize this tumor. The salient immunostaining was negativity with all routine small round cell tumor markers and positivity with CD138 and lambda light chain restriction. The heterogeneous presentation of plasmablastic lymphoma as a variant of diffuse large B-cell lymphoma and its histogenesis is documented. Potential pitfalls and differential characterization of AIDS-plasmablastic lymphoma from other closely related tumors are addressed. The importance of excluding other common pediatric small round cell tumors by immunohistochemistry is highlighted. To the best of our knowledge, this is the first report of this entity in a vertically transmitted HIV-positive child.
Hepatic angiosarcoma (HAS) is an extremely rare liver tumor in children. We report a case of childhood HAS in a six year old girl who presented with acute abdominal pain and fever with a mass in epigastrium. Left hepatic lobectomy was performed with a clinical diagnosis of hepatoblastoma. Histopathological examination revealed features typical of hepatic angiosarcoma. The case is presented for its rarity and to discuss the interrelation between infantile hemangioendothelioma (IHE) and HAS.
OBJECTIVE: We sought to study various parameters in laryngeal squamous cell carcinoma (LSCC) that might predict nodal metastasis. STUDY DESIGN AND SETTING: Sixty-four LSCCs were examined with respect to their histopathology and, using immunohistochemistry, their proliferative capacity (MIB1), p53 and cyclin D1 status, and intratumoral microvessel density. The presence of human papillomavirus was ascertained by the polymerase chain reaction. RESULTS: Histopathologically, most tumors had an infiltrating/mixed growth pattern and a diminished inflammatory reaction at the growing margin. In addition, 56% of the tumors were positive for MIB1, with 64% showing p53 overexpression; 70% were positive for cyclin D1; and 59% showed increased tumor microvessel density. Of 42 cases analyzed, 9.5% were positive for human papillomavirus 16. CONCLUSIONS: Of the parameters studied, a diminished lymphocytic inflammatory response at the periphery (P < 0.05) and cyclin D1 overexpression (P < 0.001) correlated significantly with cervical nodal metastasis at presentation. SIGNIFICANCE: Cyclin D1 overexpression, easily assessed on biopsy samples, may thus help in optimizing therapy at the outset.
Infection by high-risk human papillomaviruses (HPV) and persistent expression of viral oncogenes E6 and E7 are causally linked to the development of cervical cancer. These oncogenes are necessary but insufficient for complete transformation of human epithelial cells in vivo. Intracellular Notch1 protein is detected in invasive cervical carcinomas (ICC), and truncated Notch1 alleles complement the function of E6/E7 in the transformation of human epithelial cells. Here we investigate potential mechanisms of Notch activation in a human cervical neoplasia. We have analyzed human cervical lesions and serial passages of an HPV type 16-positive human cervical low-grade lesion-derived cell line, W12, that shows abnormalities resembling those seen in cervical neoplastic progression in vivo. Late-passage, but not early-passage, W12 and progression of the majority of human high-grade cervical lesions to ICC showed upregulation of Notch ligand and Jagged1 and downregulation of Manic Fringe, a negative regulator of Jagged1-Notch1 signaling. Concomitantly, an increase in Notch/CSL (CBF1, Suppressor of Hairless, Lag1)-driven reporter activity and a decrease in Manic Fringe upstream regulatory region (MFng-URR)-driven reporter activity was observed in late-passage versus early passage W12. Analysis of the MFng-URR revealed that Notch signaling represses this gene through Hairy Enhancer of Split 1, a transcriptional target of the Notch pathway. Expression of Manic Fringe by a recombinant adenovirus, dominant-negative Jagged1, or small interfering RNA against Jagged1 inhibits the tumorigenicity of CaSki, an ICC-derived cell line that was previously shown to be susceptible to growth inhibition induced by antisense Notch1. We suggest that activation of Notch in cervical neoplasia is Jagged1 dependent and that its susceptibility to the influence of Manic Fringe is of therapeutic value.
A two and half years old male child of sinus histiocytosis with massive lymphadenopathy, paraplegia and spinal cord involvement was treated with surgery and radiotherapy for the spinal cord compression and later with chemotherapy for his nodal disease in the neck. There was a significant improvement in his neurologic status as well as in his nodal status reiterating the role of combination therapy in this disease.
Follicular dendritic cell tumors are rare entities, which are however being increasingly recognised. One such tumor in the parapharyngeal region, diagnostically challenging, and with an unusual histological feature is reported, with a short review of the literature.