Ans: D (Brain..) Chemodectomas (Glomus Body Tumors) Dewta 7th/720-22# These are uncommon group of neoplasms that may originate anywhere glomus bodies are found.# The lesions are rare before the age of 20, there is a female predominance in some series, and the lesions may occur in multiple sites in about 10% to 20% of cases, especially in families with a history of this tumor.# These tumors usually occur later in life, around age 60 or 70, but can appear at any age. www.livestrong.com/glomus- jugulare-tumor# Carotid body tumors are associated with conditions producing chronic hypoxia, such as high-altitude habitation.# The normal glomus bodies in the head and neck vary from 0.1 to 0.5 mm in diameter. Tumors arising in glomus bodies {i.e., chemodectomas or nonchromaffin paragangliomas) arise most often from the carotid and temporal bone glomus bodies, with rare reports of tumors arising in the orbit, nasopharynx, larynx, nasal cavity, paranasal sinuses, tongue, and jaw.# The temporal bone glomus bodies are not found consistently in any location. At least one half of the glomus bodies are found in the general region of the jugular fossa and are located in the adventitia of the superior bulb of the internal jugular vein. The remainings are distributed along the course of the nerve of Jacobson (a branch of cranial nerve X).# The carotid bodies are located in relation to the bifurcation of the common carotid.Orbit bodies are in relation to the ciliary nerve, and vagal bodies are adjacent to the ganglion nodosum of the vagus nerve.Pathology# Chemodectomas are histologically benign tumors resembling the parent tissue and consist of nests of epithelioid cells within stroma-containing, thin-walled blood vessels and nonmyelinated nerve fibers. The tumor mass is well circumscribed, but a true capsule is not seen.# The criterion of malignancy is based on the clinical progress of the disease rather than the histologic picture. Chemodectomas without cellular atypia may metastasize to regional nodes or to distant organ sites.Patterns of SpreadThese lesions usually grow slowly; it is usual to have a history of symptoms fora few years and occasionally for 20 years or longer.LymphaticLymphatic metastases occur in about 5% of carotid body tumors but are very rare for temporal bone tumors. An upper neck mass may be an inferior extension of a jugular fossa or vagal tumor rather than a lymph node metastasis.Distant MetastasesDistant metastases have been rarely reported for temporal bone tumors; carotid body tumors have a low risk for distan t metastases, probably in the range of 5% or less.