Temporal Bone Histopathology Case of the Month

Facial Nerve Invasion by Basal Cell Carcinoma

*Anne L. Durstenfeld, †Amandeep Aneja, ‡Jeffrey Liu, †Heba Durra,and ‡Pamela C. Roehm

*Department of General Surgery, ÞDepartment of Pathology, and þDepartment of Otolaryngology,Temple University School of Medicine, Philadelphia, Pennsylvania, U.S.A.

CASE REPORT

A 66-year-old woman presented with 2 weeks of bloodydischarge from a 10 � 8Ycm lesion that encompassed herleft cheek and auricle (Fig. 1). Although the lesion hadbeen present for 20 years, 3 years before presentation, itbegan enlarging rapidly and ulcerating with concomitantloss of facial nerve function. Her left House-Brackmannscore was VI/VI. Preoperative MRI showed a large, ul-cerative mass of the left parotid with soft tissue invasionof the sphenoid and temporal bones and intracranialextension.

She underwent left temporal bone excision, parotidec-tomy, hemimandibulectomy, neck dissection, craniec-tomy, and TRAM flap reconstruction. Frozen sectionidentified perineural invasion of the facial nerve at thestylomastoid foramen, so it was decompressed and ex-cised to the second genu with negative margins. Finalhistologic examination revealed dense nests of basaloidcells demonstrating peripheral palisading and slit-likeseparation from stroma with focal areas of squamouskeratinization (Fig. 2A) and long thin strands and isletsof tumor cells with infiltrative edges and sclerosis. Be-cause of these findings, a mixed infiltrating sclerosingand keratotic basal cell carcinoma (BCC) was diagnosed.The neoplastic cells had invaded the underlying muscle,left auricle including cartilage, sphenoid and temporalbone (Fig. 2B), facial nerve (Fig. 2, C and D), and 2 of6 lymph nodes. Postoperatively, the patient’s clinicalcourse was uncomplicated, and she was treated withexternal beam radiation.

DISCUSSION

BCC is the most common human cancer and mostcommonly involves the head and neck. It usually grows

slowly without metastasizing and is treated by surgicalexcision with or without adjuvant radiation. BCC is char-acterized histologically by nests of hyperchromatic uniformbasaloid cells with peripheral palisading and separationfrom surrounding stroma. Immunohistochemical stainsfor Ber-EP4 and bcl-2 help to differentiate BCC fromtrichoepithelioma and squamous carcinoma. Featuresof more aggressive forms of BCC include large size,greater duration, preauricular, medial canthal, and nasalalar location, histologic subtypes other than superficialor nodular, incomplete initial excision, and perineural orperivascular invasion (1).

Perineural invasion is present in only 1% of cases ofBCC, most often in recurrent cancer and with periauricularor cheek lesions (2). Balamucki et al. (3) found that of109 SCC and BCC patients with clinical or radiologicevidence of perineural invasion, the facial nerve wasinitially involved in 26%. Our review of the English-language literature found 4 reports of facial nerve invasion

Address correspondence and reprint requests to Pamela C. Roehm, M.D.,Ph.D., Department of OtolaryngologyYHead and Neck Surgery, TempleUniversity School of Medicine, 3400 N. Broad Street, Kresge West 3rdFloor, Philadelphia, PA 19140; E-mail: pamela.roehm@tuhs.temple.edu

FIG. 1. Clinical photograph of patient demonstrating extent oftumor. This patient’s tumor had been present for at least 20 yearsand measured 8 � 6 cm.

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by BCC, three of which described facial nerve paralysisin the setting of recurrent tumors (1,4,5). Boss et al. (2)reported a case of unilateral facial nerve paralysis due toa primary BCC. Our case is remarkable for the size andinvasiveness of the tumor. Not only was there perineuralinvasion; the tumor had actually infiltrated into the nervefibers. Neoplastic spread along the nerve is a poor prog-nostic factor and indicates an aggressive lesion for whichwide margins are necessary. In a cutaneous malignancypresenting with facial nerve impairment, the surgeonshould be prepared to resect both extratemporal and intra-temporal segments of the nerve.

REFERENCES

1. Farley RL, Manolidis S, Ratner D. Aggressive basal cell carcinomawith invasion of the parotid gland, facial nerve, and temporal bone.Dermatol Surg 2006;32:307Y15.

2. Boss C,Wehner-Caroli J, RoeckenM, Ludescher B, Schaller M. Slowly-developing facial nerve paralysis. Dermatol Surg 2011;37:389Y91.

3. Balamucki CJ, Mancuso AA, Amdur RJ, et al. Skin carcinoma ofthe head and neck with perineural invasion. Am J Otolaryngol 2012;33:447Y54.

4. May M, Lucente FE. ‘‘Bell’s palsy’’ caused by basal cell carcinoma.JAMA 1972;220:1596Y7.

5. Barton JR. Diagnostic and therapeutic dilemma: facial palsyattributable to basal cell carcinoma. Am J Otol 1992;13:90Y1.

FIG. 2. Hemotoxylin and eosinYstained sections demonstrating characteristic peripheral palisading basophilic cells with slit-like sepa-ration from the surround stroma (arrow) and areas of squamous differentiation (arrowheads) (A), invasion of the temporal bone by tumor(arrows) (B), areas of perineural invasion (arrowheads) (C), and tumor infiltrating the nerve fibers of the facial nerve (arrows) (D).All photomicrographs taken at �10 magnification.

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