Laboratory Studies
A positive result with culturing in MacConkey agar is diagnostic of rhinoscleroma. However, culture results are positive in only 50-60% of patients.
Bacteria can be seen by using periodic acid-Schiff, Giemsa, Gram, and silver stains. A highly sensitive and specific method for identifying K rhinoscleromatis organisms is the analysis of a biopsy specimen with the immunoperoxidase technique.
Imaging Studies
CT findings in primary nasal and nasopharyngeal rhinoscleroma include soft-tissue masses of variable sizes. The lesions are characteristically homogeneous and nonenhancing, and they have distinct edge definition. Adjacent fascial planes are not invaded. The subglottic area is involved in laryngeal and tracheal scleroma. The lesions primarily cause concentric irregular narrowing of the airway. In the trachea, cryptlike irregularities are diagnostic of scleroma. Findings also include calcifications, luminal stenosis, wall thickening, and nodules. [33] Radiological imaging facilitates distinction from other granulomatous and malignant disorders. [34]
In persons with pseudotumoral rhinoscleromas in the septum and in the rhinopharynx, respectively, CT scanning permitted a precise evaluation of the extent of the lesions.
MRI should be performed in patients with rhinoscleroma. Nasal masses can obstruct the ostiomeatal units, and secretions may be retained in the related sinuses. In the hypertrophic stage of rhinoscleroma, both T1- and T2-weighted images show characteristic mild-to-marked high signal intensity.
Other Tests
The cytological features include a lymphoplasmacytic inflammatory infiltrate admixed with classical Mikulicz cells. [35]
Procedures
Diagnosis is facilitated by the use of cytologic methods that are easy to perform and do not cause pain in the patient (see Further Outpatient Care). Cytologic analysis is performed on brushing specimens of a lesion. [36] The characteristic cells of the Mikulicz type may be observed in the smear.
This chronic infectious disease of the upper respiratory tract is routinely diagnosed by means of tissue biopsy of the lesions.
Nasal endoscopy reveals signs of all 3 stages of scleroma: catarrhal, granulomatous, and sclerotic.
Bronchoscopy has a role in the early diagnosis of rhinoscleroma. [37]
Histologic Findings
Histopathologic analysis has a definite role in the diagnosis of rhinoscleroma. Classic histopathologic findings include large vacuolated Mikulicz cells and transformed plasma cells with Russell bodies. The Mikulicz cell is a large macrophage with clear cytoplasm that contains the bacilli; this cell is specific to the lesions in rhinoscleroma. The disease is most commonly diagnosed during the proliferative phase, in which the clinical and histologic presentations are most easily recognized.
The histologic findings correspond to the 3 clinical stages. In the catarrhal (or atrophic) stage, squamous metaplasia and a nonspecific subepithelial infiltrate of polymorphonuclear leukocytes with granulation tissue are observed. In the granulomatous stage, the diagnostic features include chronic inflammatory cells, Russell bodies, pseudoepitheliomatous hyperplasia, and groups of large vacuolated histiocytes that contain K rhinoscleromatis organisms (Mikulicz cells). If numerous, these bacteria can be seen with hematoxylin and eosin staining, but periodic acid-Schiff, silver impregnation, or immunohistochemical staining may be required to confirm their presence and identity. In the sclerotic stage, extensive fibrosis may lead to stenosis and disfiguration.
Microscopically, the connective tissue is highly vascular, with an inflammatory infiltrate consisting primarily of plasma cells and lymphocytes and a possible sprinkling of eosinophils. Russell bodies in the plasma cells are common. However, the groups, clusters, or sheets of large (100- to 200-μ m) vacuolated histiocytes (ie, Mikulicz cells) that contain the causative agent are most striking. Although the organisms are occasionally visible on standard hematoxylin and eosin stains, they are more readily demonstrated by using silver impregnation Warthin-Starry stains. The exudative stage results in a dense nonspecific fibrosis. In the exudative and cicatricial stages, Mikulicz cells may be difficult to detect. When no Mikulicz cells are evident, one looks for a heavy plasma cell infiltration without eosinophils. [38]
Electron microscopy reveals large phagosomes filled with bacilli and surrounded by a finely granular or fibrillar material that is arranged in a radial pattern. This finding represents the accumulation of antibodies on the bacterial surface (type A granules), as well as the aggregation of bacterial mucopolysaccharides surrounded by antibodies (type B granules).
See the image below.
Very high magnification micrograph of rhinoscleroma. Hematoxylin and eosin stain. Silver staining demonstrates the presence of microorganisms consistent with Klebsiella rhinoscleromatis. Courtesy of Nephron (own work), via Wikimedia Commons.
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Very high magnification micrograph of rhinoscleroma. Hematoxylin and eosin stain. Silver staining demonstrates the presence of microorganisms consistent with Klebsiella rhinoscleromatis. Courtesy of Nephron (own work), via Wikimedia Commons.
