Histological analysis of retraction pocket pars tensa of tympanic membrane in children.
OBJECTIVE
Histological and histochemical analysis of retraction pocket of pars tensa of tympanic membrane in children. Identification of morphological abnormalities in comparison with a healthy tympanic membrane as it is described in standard textbook. Identification of signs typical for cholesteatoma and support for a retraction theory of cholesteatoma formation.


METHODS
A prospective study analysing 31 samples of retraction pockets taken during surgery.
University Hospital, Children's Medical Centre


METHODS
Samples of retraction pockets were processed by a standard process for light microscopy, stained by haematoxylin-eosin. Van Gieson's stain was used for differential staining of collagen, Verhoeff's stain for elastic fibre tissues, Alcian blue for acidic polysaccharides and PAS (Periodic Acid Schiff) method for basement membrane polysaccharides.


RESULTS
The following findings were observed in the samples of retraction pockets: hyperkeratosis (100%), hypervascularisations (100%), subepithelial fragmented elastic fibres (96%), myxoid changes (87%), subepithelial inflammatory infiltration (84%), rete pegs (71%), papilomatosis (71%), intraepithelial inflammatory cellularizations, (48%), intraepithelial spongiosis (16%) and parakeratosis (3%). No basement membrane continuity interruptions were observed. Thickness of retraction pocket, thickness of epidermis, occurrence of rete pegs and frequency of fragmented elastic fibres was higher in a Grade III stage RP than Grade II stage RP (according to Charachon).


CONCLUSIONS
Morphological abnormalities in the structure of retraction pockets in comparison with a healthy tympanic membrane were described. The changes are typical for a structure of cholesteatoma (these changes are common in matrix and perimatrix), supporting retraction theory of its origin. Our observations show that it is inflammation that probably plays a key role in the pathogenesis of retraction pocket. The frequency of some of the changes increases with the stage of retraction pocket (II-III according to Charachon). Basement membrane continuity interruptions are not typical for retraction pockets.
Department of Paediatric Otorhinolaryngology, Faculty of Medicine, Masaryk University and University Hospital Brno, Czech Republic. Electronic address: docttor.urik@gmail.com.
M
M
Urík
Department of Pathology, University Hospital Ostrava, Czech Republic; Department of Pathology, Faculty of Medicine, University of Ostrava, Czech Republic; CGB laboratory, Ostrava, Vítkovice, Czech Republic.
P
P
Hurník
Department of Pathology, University Hospital Ostrava, Czech Republic; CGB laboratory, Ostrava, Vítkovice, Czech Republic.
D
D
Žiak
Department of Paediatric Otorhinolaryngology, Faculty of Medicine, Masaryk University and University Hospital Brno, Czech Republic.
J
J
Machač
Department of Paediatric Otorhinolaryngology, Faculty of Medicine, Masaryk University and University Hospital Brno, Czech Republic.
I
I
Šlapák
Nanotechnology centre, VŠB-Technical University of Ostrava, Czech Republic.
O
O
Motyka
Department of Pathology, University Hospital Ostrava, Czech Republic; Department of Pathology, Faculty of Medicine, University of Ostrava, Czech Republic.
J
J
Vaculová
Department of Pathology, University Hospital Ostrava, Czech Republic; Department of Pathology, Faculty of Medicine, University of Ostrava, Czech Republic; CGB laboratory, Ostrava, Vítkovice, Czech Republic.
J
J
Dvořáčková
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D018424:Cholesteatoma, Middle Ear / Q000473:pathology*; D003094:Collagen; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D014432:Tympanic Membrane / Q000473:pathology*
D003094:Collagen
Children; Cholesteatoma; Histological analysis; Retraction pockets