Rhinoscleroma is a chronic granulomatous infection involving the upper respiratory tract due to Klebsiella rhinoscleromatis. It initially involves the nasal mucosa but it may progress to involve any part of the upper respiratory tract. Untreated rhinoscleroma slowly progresses over many years 1.
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Clinical presentation
Patients most often present with nasal obstruction. Other nonspecific symptoms are often encountered such as epistaxis, rhinorrhea, dysphagia, stridor, and dysphonia.
Epidemiology
Patients with rhinoscleroma are usually between 10 to 30 years old. It is endemic in Central America, Egypt, tropical Africa, India, and Indonesia 3.
Risk factors
poor hygiene
prolonged close contact
malnutrition
Radiographic features
Characteristic radiological feature of rhinoscleroma is the presence of nasal mass with the following criteria 4,5:
CT
bilateral or unilateral expansile nasal masses, lesions are usually homogeneous, hyperdense and non-enhancing
masses usually extend through the nasal nares anteriorly and into the adjacent paranasal sinuses
lesions line the sinus wall causing bone sclerosis, bone thinning (pressure atrophy) or it may absorb it with extrasinus extension
no bone destruction which helps to differentiate it from malignant lesions
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in long standing cases, rhinoscleroma may extend to involve other parts of the upper respiratory tract:
such as pharynx with nodular infiltration of the oropharynx, tonsillar bed, soft and hard palate
may also show laryngotracheal involvement, the usual site of laryngeal involvement is the glottic–subglottic region showing concentric narrowing of the airway, thickening of the tracheal wall and nodular thickening of the tracheal mucosa 5
MRI
Lesions demonstrate characteristic signal intensity 4,5:
T1: mild to marked high signal intensity secondary to increased protein content within Mikulicz cells and Russell bodies
T2: hyperintense due to its high cellular component with hypointense foci of fibrosis
T1 C+ (Gd): inhomogeneous contrast enhancement secondary to areas of fibrosis
DWI: diffusion restriction with low apparent diffusion coefficients values secondary to high cellularity, which could mimic malignancy
Differential diagnosis
The differential diagnosis of nasal masses includes granulomatous and neoplastic diseases which may mimic rhinoscleroma 5.
Granulomatous diseases include:
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infectious granulomatous processes:
bacterial (tuberculosis, actinomycosis, leprosy, and syphilis)
fungal (histoplasmosis, sporotrichosis, paracoccidioidomycosis)
parasitic (mucocutaneous leishmaniasis)
non-infectious granulomatous diseases (granulomatosis with polyangiitis and sarcoidosis)
Neoplasms: such as lymphoma and sinonasal carcinoma
Findings helping differentiate rhinoscleroma from nasal malignancy:
expansion of the nasal cavities
scalloping of the sinus wall
lack of bone destruction
hyperintensity on T1
Differential diagnosis for tracheal narrowing includes: