Microdontia after chemotherapy in a patient treated for neuroblastoma: Histopathological findings

Microdontia is one of the late effects of antineoplastic therapy in children. This study is based on the comparative histological examination of abnormal, peg-shaped premolars, erupted in a patient treated for neuroblastoma, and of non-affected teeth, extracted in a healthy child. Apart from the size, the teeth vary in tissue morphology. The number of dentinal tubules, dependent on the number of odontoblasts, is smaller in the microdontal sample when observation in the same-sized field of view is conducted. Moreover, the youngest, more than 100-micrometer-thick layer of the microdontal dentin seems to be the secondary dentin, with crispy-shaped tubules and empty spaces between them. No irregular dentin is deposited in the samples of physiologically developed teeth. The structure of cementum is different as well. Unlike regularly shaped premolars, in which typical 2-layer tissue is seen, in sections of microdontal teeth, only acellular tissue with cementoblasts overlying its surface is present. Thorough analysis of drug administration effects, which are visible in microscopic sections, and of time of anticancer treatment could provide insight into the developmental mechanisms of tooth germ formation.