MALIGNANT PARAPHARYNGEAL SCHWANNOMA (NEURILEMMOMA)

653

MYRON ). SHAPIRO, MD NEWARK, NEW JERSEY

and ROBERT R. RICKERT,

MD

BY INVITATION

LIVINGSTON, NEW JERSEY

A malignant parapharyngeal neurilemmoma developed in a 45-year-old woman who had had a benign solitary neurilemmoma removed from the same area nine year. previously. Incomplete excisIon was achieved through a mandibulotomy approach.

moma is extremely rare.' Most authorities believe that schwannornasarlse de novo or, more commonly, in a preexisting neurofibroma of von Recldinghausen's disease.

Malignant schwannoma usually Is associated with neurofibromatosis and has a poor prognosis, spreading along the nerve of origin or by blood stream. Small localized tumors should be treated aggressively by surgery.

Strict criteria must be applied to the diagnosis since an erroneous diagnosis of malignancy is frequently made.' The wide variation in survival rates H may be caused by inconsistent criteria used in diagnosis.

The possibility that a previously benign schwannoma underwent malignant transformation must be considered.

SCHWANNOMAS occur anywhere a nerve has a Schwann cell sheath, arising from autonomic, spinal, or cranial nerves, especially the acoustic nerve. Most malignant neoplasms of peripheral nerves are probably of Schwann cell origin, developing in preexisting neurofibromatosis' or as a solitary malignant tumor (malignant schwannoma). It is estimated that malignancy develops in about SOfa of patients with neuroftbrornatosis.t Malignant transformation in a benign solitary neurilem-

Hypercellularity and nuclear atypism are not sufficient criteria to establish a diagnosis of malignancy. Mitotic activity and an infiltrative growth pattern together with the previously mentioned cytologic features are more reliable predictors of an aggressive biologic behavior. Although it is the most common area for the benign neoplasms, the head and neck is the site of less than 20% of the malignant variants. Only two previous case reports of parapharyngeal malignant schwan noma have been found in the literature/· s

CASE REPORT Submilled for publication Sept 12, 1978. From the Section of Otolaryngology, Department of Surgery, College of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark (Dr Shapiro), and the Department of Pathology, St Barnabas Medical Center, livingston, NJ (Dr Rickert). Presented in combination with the Committee on Surgery of the Head and Neck at the 1978 Annual Meeting of the American Academy of Otolaryngology, Las Vegas, Sept 10-13.

A 35-year-old woman was first seen in 1968 with a slowly enlarging mass in front of her left ear lobe, an occasional pins-and-needles sensation in the area, and numbness in the jaw after eating. A 1.5-cm mass was palpated deeply in the lower pole of the left parotid gland. Parotid secretions appeared normal, and there were no neurologic deficits. Aspiration biopsy

Oro/aryngo/ Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

654

SHAPIRO AND RICKERT

yielded blood y fluid from which no diagnosis could be made. At surgical exploration, a welldefined tumor mass was found deep to the facia l nerve, and, when it was removed, a second mass was discovered extending high into the parapharyngeal space. During dissection, the mass ruptured, sp illing tumor into the wound. Frozen section st ud y was reported as showing a cellular spindle cell tumor, the nature of wh ich was uncerta in. After thorough irrigatio n, metal clips were placed in the wound, and the procedure was d iscontinued. The specimen received in surgical pathology consisted of a grossly normal superficallobe of parot id gland and two segments o f well- circumscribed tumor measuring 2.0X1.5 cm and 3.0X1.5 cm . The tumor had a slightly lobulated appearance on the cut surface. Histologically, the lesion was composed of compactly arranged spindle cells growing in intertwining cords (Fig 1). The nuclei were regular in appearance, and no mitotic activity was noted. Occasional foci of nuclear pal isading were present. The appearance was typical of benign schwan noma (ne u rile mmo ma). Except for persistent weakness of the lower lip, the postoperative facial paralysis recovered in about three months, and there were no abnormal neurologic findings to ind icate lhe or igin of th is tumor.

The patient was followed up for three years, but then was not seen until October 1977, several months after she had become aware of a bulg ing mass on the left side of her soft palate (Fig 2). She complained of occas ional pain in the left side of the nose and pressure in the left eye . The mass was seen to extend into the nasopharynx, and it interfered with the left eustachian tube. No neurologic deftcits were found ; there were no palpable cervical lymph nodes. Ang iography, tomography, and xerography all outlined a large mass involving the left parapharyngeal space extending up to the base of the skull , showing erosion of the greater wing of the sphenoid (Fig 3) and demonstrating ev idence of intracran ial extension . The middle cerebral artery was elevated. Neovascularity was noted in the tumor (Fig 4). On Nov 8, 1977, the left parapharyngeal space was explored using mandibulotomy to gain access. A large, partially encapsu lated tumor was encountered and was dissected with considerable blood loss up to the base of the skull. It was firmly adherent to the pterygoid plates and pterygoid muscles and involved the foramina of the greater wing of the sphenoid as well as the foramina .lacerum, stylomastoid, and jugular. Complete removal could not be accomplished. It was believed that further

Fig 1.-Benign neurilemmoma removed from left parotid in 1968. Spindle cells are arranged in interlacing bundles. Note zone of nuclear palisading at left (arrow) (hematoxylin-eosin. x370).

Oto/aryngol Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

MALIGNANT PARAPHARYNGEAL SCHWAN NOMA

655



Fig 2.-Preoperalive appearance of recurrent tumor showing bulging of soft palate caused by parapharyngeal mass.

F ~g 4:-Subt~aclion angiographic anterior-posterior view Illustrating elevat ion of middle cerebral artery by tumor, which is outlined . Neovascular channels are easily seen.

Fig 3.-Preoperative basal view of skull show ing metal cl ips placed in 1968. Tumor is seen encroaching on nasopharynx and pterygo-maxillary space and shows destruction of greater wing of sphenoid (arrows). There is erosion of temporal bone.

surgery by th is approach would be hazardous and unjustified . The specimen received in surgical pathology consisted of two irregular masses of gray-white and yellow soh tissue measur ing 12.5X4.5X3 .0 cm and 6.0x5.0X2.5 cm in max imum dimensions. A partially circumscribed nodular mass 6 cm in diameter was contained within the larger segment of tissue. The cut surface was firm with areas of part ially cystic change (Fig 5). Microscopic sections revealed a pattern similar to that seen in the material resected in 1968. There were, however, several significant differences. The overall appearance was more cellular with slightly incre ase d nuclear hyperchromasia than in the earlier resection (Fig 6). In addition, occasional mitoses were observed .

Fig 5.-Cut surface of circumscribed but nonencapsulared recurrent tumo r. Note cystk changes.

Of particular significance was the histologic identification of focal infiltration of surrounding soh tissue and striated muscle (Fig 7). On the basis of these histologic features it was concluded that this was a low -grade malignant schwannoma . Electron microscopic studies confirmed the neural origin .

Oto/aryngol Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

656

SHAPIRO AND RICKERT



Fig 6.-Recurrenttumor. lesion is more cellular and nuclei more hyperchromatic than in lesion illustrated in Fig 1 (hernaroxyl ln-eosin, x3701.

Oto/aryngol Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

MALIGNANT PARAPHARYNGEAL SCHWAN NOMA The postoperative course, apart from the usual problems associated with mandibulotomy, was relatively benign. No neurologic signs developed that would indicate the nerve of origin. Repeat angiography confirmed the upward displacement of the middle cerebral artery. When the patient was last seen in July 1978, she was asymptomatic, her mandible had healed, and there was no gross evidence of tumor. A combined intracranial and extracranial approach is being considered, but the technical problems of successfully encompassing the lesion in its present location may not be solved.

DISCUSSION Ghosh et al,5 in their review of 115 malignant schwannomas, found that association with neurofibromatosis was indicative of a poor prognosis, while much higher cure rates were achieved with small solitary tumors. Others have not confirmed this relationship, but statistics suggest that malignant schwannomas may be either highly malignant tumors that kill almost all patients within two years or slower-growing tumors with higher survival rates.•·6•9 White 6 and Das Gupta and Brasfield? found wide variation in survival rates, which they attributed to inaccuracies in diagnosis or inadequacies in treatment. They advocated early aggressive surgical intervention, particularly to the local area. Spread of the tumor is along the nerve of origin or through the blood stream. Lymph node metastasis almost never occurs, and regional node dissection is not indicated.! The patient in this report has no stigmata of von Recklinghausen's disease, and there is no family history of it. Perineural spread is evidenced by the intracranial extension, but there is no evidence of hematogenous spread, and she is now asymptomatic. The question of whether the initial histologically benign tumor underwent

657

malignant transformation cannot be completely resolved. Although most authorities suggest that such a conversion rarely, if ever, occurs.t-z we believe that the possibility must be considered in this case. The initial tumor was typical benign neurilemmoma (schwan noma) without any histologic features suggestive of biologic aggressiveness. The recurrent lesion had a similar overall pattern but had additional features of increased cellularity, nuclear hyperchromasia, mitotic activity, and, especially, evidence of infiltrative growth with invasion of adjacent soft tissue. Two possibilities might account for this variation in histologic appearance: (1) The lesions were, in fact, identical, and because of sampling, the more aggressive component was not examined microscopically. (2) The tumor actually underwent conversion to a less differentiated form. The nine-year interval before recurrence does not contribute to a resolution of this question, since regrowth of a low-grade malignant lesion may evolve over a period of many years.

REFERENCES 1. Harkin )C, Reed RJ: Tumors of the Peripheral Nervous System. Atlas of Tumor Pathology, Armed Forces Institute of Pathology 1969, section 2, pt 3, pp 29-51, 107-121. ' 2. Abell MR, Hart WR, Olson JR: Tumors of the peripheral nervous system. Hum Pathol 1: 501-551, 1970. 3. Hiranandani LH, Hiranandani NL, Hiranandani GK: Malignant 5chwannoma. J Laryngol Otol 81 :1409-1413, 1967. . 4. Ingels GW, Campbell DC [r, Giampetro AM, et al: Malignant schwannomas of the mediastinum. Cancer 27:1190-1201, 1971. 5. Ghosh BC, Ghosh L, Huvos AG, et al: Malignant schwannoma. Cancer 31: 184-190, 1973. 6. White HR [r ; Survival in malignant schwannoma. Cancer 27:720-729, 1971.

Oto/aryngol Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

658

SHAPIRO AND RICKERT

7. Geelhoed GW, Bennett SH, Ketcham AS: Malignant schwan noma of the pharynx. ORL Digest 39:11-13, 1977. 8. Brandenburg JH: Neurogenic tumors of

the para pharyngeal space. Laryngoscope 82: 1292-1305, 1972. 9. Das Gupta TK, Brasfield RD: Solitary malignant schwan noma. Ann Surg 171:419-428,1970.

Otolaryngol Head Neck Surg 87:653-658 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV TORONTO on June 5, 2016

Malignant parapharyngeal schwannoma (neurilemmoma).

MALIGNANT PARAPHARYNGEAL SCHWANNOMA (NEURILEMMOMA) 653 MYRON ). SHAPIRO, MD NEWARK, NEW JERSEY and ROBERT R. RICKERT, MD BY INVITATION LIVINGSTO...
6MB Sizes 0 Downloads 0 Views