Page 531 - Textbook of Pathology, 6th Edition

NOSE AND PARANASAL SINUSES 515
NORMAL STRUCTURE

The external nose and the septum are composed of bone and
cartilage. On the lateral wall of the nasal cavity, there is a
system of 3 ridges on each side known as conchae or
turbinates—the inferior, middle and superior. The nasal
accessory sinuses are air spaces in the bones of the skull and
communicate with the nasal cavity. They are the frontal air
sinus, maxillary air sinus and the anterior ethmoid air cells,
comprising the anterior group, while posterior ethmoidal cells
and sphenoidal sinus form the posterior group. The anterior
group drains into the middle meatus while the posterior
group drains into the superior meatus and the spheno-
ethmoidal recess. Nasal mucous membranes as well as the
lining of the nasal sinus are lined by respiratory epithelium
(pseudostratified columnar ciliated cells). Mucous and serous
glands underlie the mucous membrane. Besides, the upper
Figure 18.10 Cholesteatoma middle ear. There is chronic and middle turbinate processes and the upper third of the
inflammatory granulation tissue and foreign body giant cells around the septum are covered with olfactory mucous membrane.
cholesterol clefts and some pink keratinous material.
The main physiologic functions of the nose are smell,
filtration, humidification and warming of the air being
present through which the squamous epithelium enters the breathed.
middle ear and results in exfoliation of squamous and
formation of the keratin. Rarely, it may be a primary lesion INFLAMMATORY CONDITIONS
arising from embryonal rests of squamous epithelium in the CHAPTER 18
temporal bone. ACUTE RHINITIS (COMMON COLD). Acute rhinitis or
common cold is the common inflammatory disorder of the
Histologically, the lesion consists of cyst containing nasal cavities that may extend into the nasal sinuses. It begins
abundant keratin material admixed with cholesterol with rhinorrhoea, nasal obstruction and sneezing. Initially,
crystals and large number of histiocytes (Fig. 18.10). In the nasal discharge is watery, but later it becomes thick and
advanced cases, there may be pressure erosion of the bone. purulent. The etiologic agents are generally adenoviruses that
evoke catarrhal discharge. Chilling of the body is a
JUGULAR PARAGANGLIOMA (GLOMUS JUGULARE contributory factor. Secondary bacterial invasion is common.
TUMOUR, NON-CHROMAFFIN PARAGANGLIOMA). The nasal mucosa is oedematous, red and thickened.
Tumours originating from parasympathetic ganglia are The Eye, ENT and Neck
called ‘paraganglioma’ and are named according to the Microscopically, there are numerous neutrophils,
location of the tissue of origin. The one arising from glomus lymphocytes, plasma cells and some eosinophils with
jugulare bodies of the middle ear (jugulotympanic bodies) abundant oedema.
is called jugular paraganglioma or chemodectoma or non- ALLERGIC RHINITIS (HAY FEVER). Allergic rhinitis
chromaffin paraganglioma and is the most common benign occurs due to sensitivity to allergens such as pollens. It is an
tumour of the middle ear. Histologically similar tumours are IgE-mediated immune response consisting of an early acute
seen in the carotid bodies and vagus (Chapter 27). response due to degranulation of mast cells, and a delayed
prolonged response in which there is infiltration by
Microscopically, the tumour cells containing neuro- leucocytes such as eosinophils, basophils, neutrophils and
secretory granules are arranged in typical organoid macrophages accompanied with oedema.
pattern or nests. The tumour may extend locally to involve
the skull and brain but may rarely metastasise. SINUSITIS. Acute sinusitis is generally a complication of
acute or allergic rhinitis and rarely secondary to dental sepsis.
ACOUSTIC NEUROMA (ACOUSTIC SCHWANNOMA). The ostia are occluded due to inflammation and oedema and
This is a tumour of Schwann cells of 8th cranial nerve the sinuses are full. ‘Mucocele’ is filling up of the sinus with
(page 893). It is usually located in the internal auditory canal mucus while ‘empyema’ of the sinus occurs due to collection
and cerebellopontine angle. It is a benign tumour similar to of pus. Acute sinusitis may become chronic due to incomplete
other schwannomas but by virtue of its location and large resolution of acute inflammation and from damage to the
size, may produce compression of the important mucous membrane. Sinusitis may rarely spread to produce
neighbouring tissues leading to deafness, tinnitus, paralysis osteomyelitis and intracranial infections.
of 5th and 7th nerves, compression of the brainstem and NASAL POLYPS. Nasal polyps are common and are
hydrocephalus. pedunculated grape-like masses of tissue. They are the end-