Olfactory neuroblastoma (esthesioneuroblastoma). A light and ultrastructural study of two cases

Abstract

Olfactory neuroblastoma is a malignant neoplasm with a varied biological behavior. Its clinical course is unpredictable and there is no correlation between its microscopic features and biological behavior. The present study deals with light and ultrastructural characteristics of two cases of olfactory neuroblastoma of the nasal cavity. In one patient, the definitive diagnosis was established on the basis of ultrastructural features of the lesion. The most consistent fine structural findings were the presence of intracytoplasmic densecored neurosecretory granules, "true" and "pseudo-" rosettes, and the neuritic processes emanating from the tumor cells. On the basis of their biochemical, histochemical, and ultrastructural characteristics, olfactory neuroblastomas are similar to neuroblastomas arising from the adrenals or sympathetic nervous system. These findings, therefore, support the hypothesis that olfactory neuroblastomas are most likely of neural crest origin and thus belong to a group of neoplasms collectively known as "apudomas" or neurocristomas. The literature review strongly favors combined surgery and postradiation as the most effective treatment of olfactory neuroblastoma.

Olfactory Neuroepithelioma in a Dog: An Immunohistochemical and Electron Microscopic Study.

“…Reported ultrastructural studies on so-called olfactory neuroblastoma frequently demonstrated dense-cored or membrane-bound secretory granules in the tumor cells [6,25], while no dense-cored secretory granules were found in esthesioneuroepitheliomas [9,11,23]. In this study, tight junction being a character of the epithelial cells was observed but no sign of secretory granules.…”

“…Thus not only the histological diagnosis but also the origin of the tumor is still a matter of controversy in humans as evidenced by the different terms used to describe the tumor [24]. These include olfactory neuroblastoma [6,8,18] Takahashi et al [23] suggested that their cases consisted of cells differentiating in at least two distinct directions, neuronal and epithelial, and concluded that the tumors were of true olfactory epithelium origin, or more precisely, derived from the bipotential, undifferentiated basal cells of the epithelium and differed from olfactory neuroblastomas which are generally considered to be "APUD (amine precursor uptake and decarboxylation) tumors". Based on these findings, the term of olfactory neuroepithelioma was added in the category of olfactory neuroblastoma as a new variant in the WHO classification of human tumors [20].…”

“…Thus not only the histological diagnosis but also the origin of the tumor is still a matter of controversy in humans as evidenced by the different terms used to describe the tumor [24]. These include olfactory neuroblastoma [6,8,18], olfactory esthesioneuroblastoma [4,14], esthesioneurocytoma [2], esthesioneuroepithelioma [3], olfactory neuroepithelioma [21], intranasal neuroblastoma [19], and olfactory placode tumor [26]. Immunohistochemically, the tumor provided a variable number of cells positive for neurofilament protein, keratin, neuronspecific enolase and S-100 [23].…”

“…The olfactory epithelium is composed of three cell types: the neurosensory cells (olfactory cells) extending their axons to the olfactory bulb; the sustentacular cells being the supportive element; and the basal cells having a potential of differentiation to either neurosensory cells or sustentacular cells [6]. None of these cells normally contains neurosecretory granules.…”

“…These olfactory structures are considered to be originated from the ectodermal placodes [13]. Ultrastructurally, reported olfactory neuroblastomas in both humans and animals frequently contained neurosecretory granules, leading researchers to believe that these tumors originated from regional neural crest tissue rather than from the olfactory epithelium [6,7]. Based on the findings from immunohistochemistry and electron microscopy, Hassoun et al [9] and Takahashi et al [23] concluded that cases of the olfactory neuroblastomas contained a rare variant, olfactory neuroepithelioma/esthesioneuroepithelioma, which was a true neurosensorial tumor originating from the olfactory epithelium and differed from reported so-called olfactory neuroblastomas which were generally considered to be "APUD tumors".…”