JOS system 2016（日本耳科学会案）
Staging and Classification for Middle Ear Cholesteatoma
Auris Nasus Larynx, 44( 2):135–40, 2017 (Published online: September 9, 2016)

Classification of Middle Ear Cholesteatoma
I. Acquired cholesteatoma
1) Retraction pocket cholesteatoma (so-called primary acquired cholesteatoma)a) Pars flaccida cholesteatoma (Attic cholesteatoma)b) Pars tensa cholesteatomac) Combination of pars flaccida and pars tensa cholesteatoma
2) Non retraction pocket cholesteatomaa) Cholesteatoma secondary to a chronic tensa perforation(so-called secondary acquired cholesteatoma)b) Transplanted cholesteatoma following trauma or otologic procedures
II. Congenital cholesteatoma
III. Unclassifiable cholesteatoma

Staging of Middle Ear Cholesteatoma
1. Divisions of the middle ear space (PTAM system)
A

Schematic drawing of divisions of the tympanomastoid space. The
tympanomastoid space is divided into four sections: the protympanum(P), the tympanic cavity (T), the attic (A) and the mastoid (M) in orderto represent the extent of cholesteatoma.

PMT

2. The JOS staging system applies to 4 types of middle ear cholesteatoma(Pars flaccida cholesteatoma, pars tensa cholesteatoma, congenital cholesteatoma and cholesteatoma secondary to a tensa perforation)

Stage I
Cholesteatoma localized in the primary site** The site of cholesteatoma origin, i.e. the attic (A) for apars flaccida cholesteatoma; the tympanic cavity (T) forpars tensa cholesteatoma, congenital cholesteatoma andcholesteatoma secondary to a tensa perforation.

Stage II
Cholesteatoma involving two or more sites

Stage III
Cholesteatoma with extracranial complications and/orintratemporal pathologic conditions
Facial palsy (FP), labyrinthine fistula (LF): with conditions at risk for
MC0
membranous labyrinth, labyrinthine disturbance (LD):scale out BC
values for more than two speech frequencies (0.5, 1, and 2kHz),canal wall destruction (CW): more than half the length of the bony
ear canal, adhesive otitis (AO): total adhesion of the pars tensa,
petrous bone or skull base destruction (PB), neck abscess (NA).

Stage IV

MC1
Cholesteatoma withintracranial complications including
MC2

Purulent meningitis, epidural abscess, subdural abscess,brain abscess, sinus thrombosis, etc.

3. Sub-classification of stage I for respective cholesteatoma types
Pars flaccida cholesteatoma

Cholesteatoma secondary to a tensa perforation

Stage I: Cholesteatoma localized in the attic
Stage Ia: A retraction pocket with epithelial self-cleaning function
Stage Ib: A retraction pocket with persistent accumulation ofkeratin-debris

Stage I: Cholesteatoma localized in the tympanic cavity
Stage Ia: Epithelial invasion confined to the underside of the pars tensa
Stage Ib: Epithelial invasion extending to the tensor tympani tendon andthe promontrial wallPars tensa cholesteatoma

Congenital cholesteatoma

Stage I: Cholesteatoma localized in the tympanic cavity
Stage Ia: A retraction pocket with epithelial self-cleaning function
Stage Ib: A retraction pocket with persistent accumulation ofkeratin-debris

Stage I: Cholesteatoma localized in the tympanic cavity
Stage Ia: Cholesteatoma confined to the anterior half of the tympanic cavity
Stage Ib: Cholesteatoma confined to the posterior half of the tympanic cavity
Stage Ic: Cholesteatoma involving both of sides of the tympanic cavity