A rare case of carcinoma ovary presenting as isolated unilateral hypoglossal nerve palsy

Introduction

The hypoglossal nerve is the pairedtwelfth cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue, and the depressors of the hyoid bone, thus controlling all movements of the tongue required for speech and swallowing, including sticking out and moving from side-to-side. Damage to the nerve or the neural pathways which control it can affect the ability of the tongue to move, its appearance, and swallowing and speech difficulties. Vascular, inflammatory, traumatic, or space-occupying lesions can affect the twelfth cranial nerve anywhere in its course, from the nucleus in the caudal medulla, through the intracranial extramedullary portion of the nerve, across the hypoglossal canal, or into its extra cranial termination.¹ Hypoglossal nerve palsy usually presents with additional neurological symptoms, its presentation in isolation is rare.² Till now very limited single cases of isolated hypoglossal nerve palsy and small case series have been published which is evident from the literature.^3,4 So we are reporting a case of isolated unilateral hypoglossal nerve palsy due to metastasis from malignant left ovarian carcinoma.

Case Report

A 60 years old woman presented to the general medicine department of Khaja Banda Nawaz Institute of Medical Sciences with a history of headache, severe backache and abdominal pain since 2 months and difficulty in chewing, swallowing and slurring of speech since 15days, who was diagnosed with left malignant ovarian carcinoma 3 years back. She underwent 8 cycles of neoadjuvant chemotherapy followed by total abdominal hysterectomy with bilateral salpinooophrectomy. After surgery, she was regularly followed up, and no distant metastasis or local recurrence was detected by serial imaging studies or laboratory examinations. She was asked to continue the chemotherapeutic agents and with that she remained symptom free for a period 2.5 years. Approximately from 2 months, she started to develop the present symptoms.

The patient had headache which was situated over the left half of the head, throbbing type, radiating to neck and left shoulder associated with nausea and vomiting. There was no history of fever, convulsions, weakness of limbs, diplopia, deviation of angle of mouth, drooping of eye lids, loss of taste sensation, blurring of vision. On general examination, pallor was the only positive finding. The vitals were within normal limits. Neurological examination revealed deviation of tongue to the left side on protrusion and wasting of muscles on the left side of the tongue [Fig. 1]. The motor function was affected but the sensory function was intact. Other cranial nerves examination was normal. No other neurological deficits were elicited. Abdominal examination showed liver enlargement of around 6cms below the costal margin which was hard in consistency and showed irregular borders. Other system examination was normal. USG abdomen showed hepatomegaly with metastatic hypoechoic mass lesions, the bigger one in the right lobe of liver measuring 9.5x 9cms [Fig.2]. MRI spine showed skeletal metastasis to sacral vertebral bodies with anterior epidural small soft tissue component [Fig. 3].Magnetic resonance imaging (MRI) of brain and the base of skull tracing the hypoglossal canal and the hypoglossal nerve throughout its course revealed left sided carcinomatous infiltration of hypoglossal nerve [Fig. 4]. During the hospital stay, patient aspirated and went into respiratory failure and died.

Discussion

Isolated hypoglossal nerve palsy is uncommon because of its intimate relationship with the other lower cranial nerves. Excluding previous surgery, radiotherapy and trauma, 50 per cent of cases of isolated hypoglossal nerve palsy are idiopathic. A further 20per cent are malignant, 20 per cent are of a vascular causesuch as dolichoectasia of the vertebral artery and dissection of extra cranial internal carotid artery. The remaining 10 per cent are due to miscellaneous causes.² Hypoglossal nerve palsy tends to occur as a sign rather thana symptom5and therefore warrants thorough investigation.

Keane et al. reported his personal experience of 26 years on hypoglossal nerve palsy in 100 patients with or without the involvement of other brain stem structures. He found neoplastic etiology in 85% of his cases, thus emphasizing that isolated hypoglossal nerve palsy often heralds an ominous prognostic sign.⁵ But Bhawna Sharma et al in the their case series of 12 patients found that treatable causessuch as tubercular central nervous system infection(33%) and idiopathic (25%) cases overweighed the neoplastic (16%) etiology. Sarcoidosis (8%), atlanto occipital dislocation (8%) and aberrant ectatic vessel in the hypoglossal canal (8%) were contributory in the remaining cases6.The case series study of isolated HNP in 9cases by Combarros et alreported idiopathic hypoglossal nerve palsy in 4cases, metastasis in 3 cases, Arnold Chiari malformation in 1 case and dural AV fistula in 1 case.³ Another case series of 4 patients with isolated HNP by Marina Boban et al,² cases had malignant etiology.⁴

Common primary tumors with metastases to the base of the skull include those of the breast, lungs, and prostate, whereas relatively rare tumors involving such a complication are renal cell carcinoma, thyroid cancer, and melanoma. In most cases, tumor cells metastasize to the base of the skull or the calvarium via hematogenous arterial circulation.⁷ Alternatively, direct extracranial extension through the skull base in head and neck malignancy could be another differential diagnosis. Although skull metastases from malignancy are not uncommon, they are often neglected owing to their asymptomatic nature and limited localized pain. Most are not detected until signs and symptoms from the stretching of the dura, compression of the cranial nerves, and irritation (with resulting edema) of the adjacent brain tissue, and, less commonly, occlusion of the dural venous sinuses are observed.⁸ Thenerve can be involved anywhere along its course. Hence localization of site of lesion is very important.

Distant metastases are common but unusual at presentation in case of ovarian carcinoma. Cormio et al in their study of 162 ovarian carcinoma patients, found 67 metastatic sites in 50 patients. Central nervous system metastasis was found in 7 cases.⁹ Pakneshan et al, in their studyof 591 patients with ovarian carcinoma, majority of patients (57.3 %) had multiple brain metastases. The location of the lesion was cerebellar (30 %), frontal (20 %), parietal (18 %) and occipital (11 %).¹⁰ But in our case, the patient’s MRI did not show any metastasis to brain. Instead we found metastatic infiltration of the left hypoglossal nerve. So, this is a unique case of isolated unilateral hypoglossal nerve palsy in a patient who remained symptom free for 2.5 years after treatment for malignant ovarian cancer due to malignant infiltration of the nerve. Thus, careful imaging of the brain, skull base and cervical spine should be performed, especially if Hypoglossal nerve palsies develops.

Conclusion

The distant metastasis of ovarian carcinoma can present as cranial nerve palsy even without any brain metastasis. This case report once again serves to remind clinicians the importance of a systematic approach and detailed investigation to rule out malignancy and other underlying causes.