Leiomyosarcoma of the Middle Ear and Temporal Bone
A 54-year-old man presented with 4-month history of otorrhea and a rapidly growing mass on the external auditory canal and postauricular area after open cavity mastoidectomy at other hospital 5 months ago. He was otherwise healthy, with no significant medical history. He had received no previous radiotherapy. Physical examination revealed polypoid mass totally packed in external auditory canal and exophytic mass about 5×4 cm in postauricular area ().\nNo cervical lymph nodes were palpitated. No facial paralysis was present. The scalp and the remainder of the findings on otolaryngologic examination were within normal limits. Audiometry demonstrated a mixed hearing loss of 50 dB of bone conduction and 90 dB of air conduction hearing. Routine clinical laboratory data and a chest radiograph were normal. Two biopsies were performed. Histologic evaluation identified the lesion as a leiomyosarcoma with extensive necrosis.\nComputed tomography (CT) of the temporal bone demonstrated a mass in the middle ear cavity, with absence of almost the entire temporal bone due to previous operation and with destruction of a part of petrous bone. The inner ear structures were preserved ().\nMagnetic resonance imaging (MRI) indicated a mass expending to pterygoid muscles, posterior margin of mandible and middle and posterior cranial fossa dura. The lesion obstructed the external auditory canal and could not be demarcated with granulation tissue ().\nFor the en bloc excision of the mass, the clear margin was 1.5 cm or more. The auricle was sacrificed for the design of surgical incision with the discolorated skin.\nThe excisions of the temporal bone was conducted including the external auditory canal, the middle ear, the vestibular organ, middle and posterior fossa dura, and the partial petrous bone. The cochlear, the lateral sinus, and the jugular bulb remain intact (). For the preservation of facial nerve function, the delicate epineural dissection of facial nerve was performed from tympanic segment to stylomastoid foramen and the fascicle of facial nerve was solely remain in middle ear cavity like as a clothesline (). Complete tumor excision was confirmed by a frozen section from surgical boundaries.\nThe main mass did not invade the dura of middle cranial fossa or posterior cranial fossa, but came in direct contact with that. For the clear margin from the mass-contacted surface, the resection of the dura located on the middle cranial fossa was designed about 4.5×2.5 cm size and ovoid shape and the dura located on the posterior cranial fossa was designed about 2.5×2.5 cm size and round shape (). The repair of the dura was done with Lyodura and reinforced with Gelform ().\nThe pectoralis major myocutaneous flap was advanced and transposed to cover the temporal defect with protecting the fascicle of facial nerve using a piece of the muscle flap. The approximation of the pectoralis muscle flap was done without tension to the defect area (). The specimen after en-bloc resection was shown on .\nSpecimen were fixed in 10% formaldehyde solution, which contained a 0.1 molar phosphate buffering system (Ph=7). Slide stained with H&E were examined under the microscope. The tumor composed of spindle cells with cigar-shaped nuclei. Nuclear atypia was present. Cytoplasmic vacuoles were located at both ends of the nucleus (). Histopathological examination indicated the diagnosis of grade 3 leiomyosarcoma (30 mitoses/10 high power fields). There was no infiltration of tumor into epineurium of facial nerve, dura of middle and posterior cranial fossa, and Eustachian tube orifice.\nThe facial nerve function was well preserved as House-Brackmann grade II after epineural dissection of facial nerve (). There was no invasion of tumor into the epineurium of facial nerve in pathological finding and the fascicle of facial nerve in surgical finding. Although postoperative wound healing was delayed due to cerebrospinal fluid leakage to wound site for several days, but it did not cause any problem. There was not been seen any recurrence or metastasis.