A Case of Apoplexy of Rathke's Cleft Cyst Followed by Cerebral Infarction

Rathke's cleft cyst (RCC) apoplexy is a rare clinical entity. We report a case of apoplexy of an RCC followed by cerebral infarction. A 67-year-old woman was found lying on the street unconscious. She had fallen from her motorbike. On referral to our hospital she gradually regained consciousness and presented with no neurological deficits. CT showed a round and slightly hyperdense area in the suprasellar region. However, the attending physician did not find this abnormal finding on CT and the patient was discharged the same day. Thirteen days after the first emergency visit she developed left hemiparesis and dysarthria. CT showed a round hypodense area in the suprasellar region. The change of the density in the suprasellar region on CT suggested the pituitary apoplexy. CT also showed a low density area in the territory of the right middle cerebral artery, which indicated the cerebral infarction. MR angiography revealed poor visibility and stenotic changes of right middle cerebral arteries. Transsphenoidal surgery was performed. Histopathological findings confirmed a hemorrhagic RCC. Postoperative MR angiography showed that the visibility and stenosis of right middle cerebral arteries were recovered. This is the rare case of apoplexy of an RCC followed by cerebral infarction.


Case Report
A 67-year-old woman was found lying on the street unconscious. She had fallen from her motorbike. On referral to our hospital she gradually regained consciousness and presented with no neurological deficits. She had a facial abrasion, but no headache and no nausea. CT showed a round and slightly hyperdense area in the suprasellar region (Figure 1(a)). However, the attending physician did not consult a neurosurgeon and the patient was discharged the same day. This physician overlooked a significant appearance in the suprasellar region.
Thirteen days after the emergency visit, she gradually developed left hemiparesis. Other neurological signs were within normal limits. Arterial blood gas measurement did not reveal acidemia or alkalemia. Routine laboratory tests were normal, and the patient was neither diabetic, nor hypertensive, nor hyperlipidemic. Endocrinological tests also detected no abnormalities. Echocardiographic examination and carotid artery ultrasound examination showed no abnormalities, and the electrocardiogram was also normal.
CT on admission showed a round hypodense area in the suprasellar region (Figure 1(b)). The change of the density in the suprasellar region on CT suggested the pituitary apoplexy. Magnetic resonance imaging (MRI) taken 2 days after admission detected isointensity on T1WI and high intensity on T2WI in the suprasellar region ( Figure 2). CT also showed a low density area in the territory of the right MCA, which indicated the cerebral infarction ( Figure 1(c)). MR angiography (MRA) showed signal loss with poor visibility of distal right middle cerebral arteries (MCAs) (Figure 3). The conservative treatment for cerebral infarction improved her left hemiparesis. Ten days after admission, endoscopic endonasal transsphenoidal surgery was performed. The sella turcica was found to be thin. The tumor contained white-tinged viscid fluid. A normal pituitary gland was observed on the right side. Histopathological findings confirmed hemorrhagic RCC (Figures 4(a) and 4(b)). The cyst wall was lined by a ciliated columnar cell layer with goblet cells. Thin blood vessels were observed in the cyst wall. Red blood cells were seen in both cyst and cyst wall. Postoperative MRI showed the decompression of suprasellar region ( Figure 5). Postoperative MRA revealed partial stenotic changes of right MCAs ( Figure 6). These findings suggested RCC apoplexy followed by cerebral infarction.

Discussion
RCC apoplexy is a rare clinical entity. Fourteen cases of apoplexy of RCC have been reported in the literature (Table 1) [6][7][8][9][10][11][12][13][14][15][16][17]. The mechanism of RCC apoplexy is supposed to be the repeated minor bleeding from the thin blood vessels in the cyst wall by the stimulation of cyst contents and the bleeding from the hypophyseal portal blood vessels by the compression or shearing stress [7,15]. The clinical presentations of these cases were headache, nausea, visual disturbance, and cranial nerve palsy. One case in Table 1 presented with altered consciousness as our case did. Nawar et al. reported 11 cases with hemorrhage within RCC [14]. In their study, although not described in detail of each case, respectively, there were 3 patients with altered consciousness, there were 10 patients with headache, there were 3 patients with a visual deficit, and there was 1 patient with cranial nerve palsy.
The pituitary apoplexy is caused by the anticoagulant therapy, the bromocriptine therapy, the radiation therapy, the hormone loading test, the cerebral angiography, and the cardiovascular surgery [18]. Particularly in macroadenoma, the head trauma can cause the apoplexy between 0 days and 21 days [19][20][21]. None of these reviewed cases of RCC apoplexy were caused by the head trauma. In our case, it was unclear whether the unconsciousness at the first emergency visit depended on the head trauma or apoplexy.
Preoperative endocrinological evaluations revealed abnormalities in 4 cases (Table 1). Wakai et al. described that preoperative endocrinological examinations revealed abnormalities in 3 cases. Most pituitary apoplexy cases need hormone replacement therapy for partial hypopituitarism [6]. In our case the preoperative endocrinological examinations were normal.
A rare complication of pituitary apoplexy is cerebral infarction, which is caused by either direct compression of an artery or vasospasm. Twenty cases of pituitary apoplexy followed by cerebral infarction have been reported in the literature (Table 2) [1, 20, 22-24, 26, 28, 29, 31-39]. The ischemic events were attributed to mechanical compression by the tumor in 12 cases and to cerebral vasospasm in 8 cases. The cerebral infarction was located at the anterior cerebral artery (ACA) territory in 4 cases, the MCA territory in 8 cases, and the ICA territory in 4 cases. Cerebral arterial stenosis was detected in the ICA in 15 cases, in the MCA in 3 cases, and in the ACA in 3 cases. The cerebral infarction occurred between 0 and 21 days after the onset of pituitary apoplexy. Most infarctions due to cerebral vasospasm occurred between 5 and 21 days after onset, and all infarctions by mechanical compression occurred within 2 days after onset.
In our case, the cerebral infarction occurred in the right MCA territory after a 13-day interval from the onset of RCC Case Reports in Neurological Medicine Figure 2: Axial, sagittal, and coronal views of the MRI showed isointensity on T1WI (a, e, and g) and high intensity on T2WI (b, f, and h) in the suprasellar region. Axial and coronal views of the MRI presented isolow intensity on T1WI (c, g) and high intensity on T2WI (d, h) in the territory of the right middle cerebral artery.

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Case Reports in Neurological Medicine    apoplexy. MRA revealed the stenotic lesion of the right MCA, and echocardiogram, electrocardiogram, and carotid artery ultrasound showed no abnormalities. These clinical findings could exclude the embolic cause of the ischemic lesion. Our case was neither hyperlipidemic nor hypertensive. CTA and carotid artery ultrasound presented no artherosclerotic changes. These clinical findings could exclude the possibility of the artherosclerotic brain infarction. Postoperative MRA and CTA showed that the visibility and stenosis of right MCAs were recovered. Therefore together these findings suggested that the etiology of the cerebral infarction was cerebral vasospasm. The pathology of vasospasm following pituitary apoplexy is unclear; however, vasoactive chemical substances released during pituitary apoplexy may cause vasospasm [20,28,35]. The subarachnoid hemorrhage (SAH) causes the vasospasm, but the pathological mechanism also remains unclear [27]. The endothelin, angiotensin, and sphingosine metabolites are one of the vasoactive substances, respectively [5,25,30].
Although the CT and MRI detected no SAH in our case, vasoactive substances liberated from the hemorrhagic RCC or SAH below levels in detection by CT and MRI might cause the vasospasm.
This patient had fallen from her motorbike. She was disoriented and had a facial abrasion. Considering head trauma, the attending physician examined head CT. This physician Case Reports in Neurological Medicine 7 overlooked a significant appearance in the suprasellar lesion. Therefore the attending physician did not consult a neurosurgeon.
Asymptomatic incidental RCC should be monitored conservatively. Symptomatic RCC can benefit from surgical decompression, and RCC apoplexy should be considered the surgical decompression to prevent cerebral infarction, even if symptoms resolve soon after onset.