title: Histopathologic changes following neoadjuvant chemotherapy in various malignancies.
abstract: BACKGROUND
  Various histopathological changes have been observed following neoadjuvant chemotherapy in individual tumors in the literature.
  
  
  OBJECTIVE
  To observe histopathologic changes seen after neoadjuvant chemotherapy in breast malignancies, squamous cell carcinomas, adenocarcinomas, and Wilms' tumor using breast cancer predominantly as the model.
  
  
  METHODS
  The present prospective study was carried out on 60 patients including 40 patients with carcinoma breast and 20 patients with other malignancies who received neoadjuvant chemotherapy.
  
  
  RESULTS
  Post neoadjuvant chemotherapy, mastectomy specimens revealed nuclear enlargement, nuclear shrinkage, necrosis, vacuolation of nucleus, vacuolation of cytoplasm, dyscohesion, and shrinkage of tumor cells with nuclear changes of nonviability like karyorrhexis, karyolysis, and pyknosis. Stromal reactions manifested as fibrosis, elastosis, collagenization, hyalinization, microcalcification, and neovascularization. Areas of necrosis included both vascular and avascular pattern. The stroma also revealed fibrinoid necrosis and mucinous change. Hyalinization of the blood vessel wall was a common finding. The most common inflammatory host response observed in the present study was lymphocytic; others included mixed inflammation, plasmacytic, prominent histiocytic, and giant cell types. Giant cell reaction was significantly correlated to all types of tumor responses (P < 0.05). Similar changes were also observed in other malignancies. A detailed review of the literature has also been done and presented.
  
  
  CONCLUSIONS
  The tumor grade decreases and differentiation improves, in addition to the retrogressive changes and increase in stromal component, as a result of chemotherapy in carcinoma breast as well as in other malignancies.
authors.affiliation: Department of Pathology, PGIMS, Rohtak, India.
authors.forename: Divya
authors.initials: D
authors.lastname: Sethi
authors.forename: Rajeev
authors.initials: R
authors.lastname: Sen
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Parshad
authors.forename: Sheena
authors.initials: S
authors.lastname: Khetarpal
authors.forename: Monika
authors.initials: M
authors.lastname: Garg
authors.forename: Jyotsna
authors.initials: J
authors.lastname: Sen
keywords: Breast carcinoma; changes following chemotherapy; neoadjuvant chemotherapy