A Rare Case of Intramedullary Lipoma of Brainstem to Thoracic Cord--What to Do?

INTRODUCTION: Intramedullary lipomas are rare, representing 1% of spinal cord tumors. There are less than 25 case reports about cord lipoma extending into brain. Due to paucity of literature, etiology and management are not well established. CASE REPORT: A 14-month-old baby girl was brought with complaints of torticollis toward right side, left upper limb monoplegia, and swallowing difficulty for 6 months. Magnetic resonance imaging brain and spine confirmed the diagnosis of cervicothoracic intramedullary lipoma extending till pontomedullary junction, invading subcutaneous fat. She underwent partial resection of lesion along with decompression. The recovery was good.
CONCLUSION: Such lipoma needs extensive pre-, intra-, and postoperative planning. The goal should be decompression, rather than excision. Outcome is good with partial resection. Copyright:

INTRODUCTION

Intramedullary lipomas are either dysraphic or non-dysraphic.[123] Both types are rare, representing 0.06%–0.46% of intracranial lesions and <1% of spinal lesions.[23] There are few reports about extremely rare cases of craniospinal non-dysraphic lipoma.[1234] It presents unique challenges to neurosurgeon: both cranial and spinal involvement requiring extensive exposure, involvement of both brainstem and cord parenchyma, no clear plane between lesion and normal tissue, and no definitive guideline. This case report is about what to do to get satisfactory outcome in such type of lipoma based on our experience and review of existing literature.

CASE REPORT

A 14-month-old baby girl was brought with complaints of progressive torticollis right side [Figure 1A], weakness of left upper limb (UL) progressed to monoplegia [Figure 1A] for 6 months, and swallowing difficulty for 1 month. She had episodes of regurgitation of food. On examination, she was conscious, active except left UL weakness and neck tilt, and irritable due to hunger. She had black colored pigmented spots with thick dark colored skin on the left side of nap of neck [Figure 1B and C]. It was pulsatile [Video 1] and non-tender. Magnetic resonance imaging (MRI) brain and cervicothoracic spine revealed intramedullary lipoma of cervicalthoracic cord from D2 to pontomedullary junction, having exophytic component on the left-side brainstem and cord [Figure 2A–F]

Figure 1

(A) Preoperative image of child, showing torticollis (head tilt) right side, left upper limb supported by bed. Her right upper limb is holding knee and providing support. (B) Dorsal aspect of neck having multiple dark colored pigmented spots on left side, from occiput till D2. (C) Marked area, which had visible pulsations. (D) Postoperative follow-up image showing correction of torticollis and functional left upper limb. She was able to hold object.

Figure 2

(A) T2 sagittal MRI brain and spine showing iso-intense irregular intramedullary lesion extending from pontomedullary junction till D2 level, which is also going till subcutaneous region. (B) T1 sagittal MRI brain and spine showing lesion, which is hyperintense just like fat. (C) T1 axial cut of C3 showing hyperintense lesion arising from cord on left side, infiltrating left neural foramina and pushing cord toward right and anterior side. (D) T2 coronal cut showing iso- to hyperintense lesion and its relation with vertebral artery (red arrow), which is pushed anteriorly. (E) T1 axial cut of medulla showing hyperintense lesion present on left side, vertebral artery (flow void) in its anterior tip, pushing medulla on right side. (F) T2 axial cut of medulla showing lesion on left side with left jugular foramen extension (red dot). The significance of red arrow (Fig 2D) and red dot (Fig 2F) has been clearly explained in figure legend. It is depicting relation with vertebral artery (red arrow) and extension (red dot).

The plan was to decompress the cord and remove lipoma without damaging parenchyma. Linear vertical incision was given from occipital protuberance till D3. There was subcutaneous lipoma continuing with cervical lipoma [Figure 3A and B]. The posterior arch of C1 was absent [Figure 3B]. Midline suboccipital craniotomy and laminectomy of C2–D1 were carried out [Figure 3C]. Dura was identified at all levels except C1–2 level. The lipoma was originating from the left lower part of ventral side of medulla oblongata and dorsal cervicothoracic cord. It was almost completely occupying the canal at C1–3 level, whereas cord could be identified below it and on the right side. It was pressing left 9th–11th nerves and entering jugular foramen. Partial decompression was carried out [Figure 3D]. After decompression, duroplasty was carried out with subcutaneous fat and glue [Figure 3E]. We did not consider fusion of spine to prevent future instability because of young age, unfused spine, avoid any obstacle for future growth of vertebrae. The surgical duration was 10 hours. There was around 200ml blood loss, which was replaced intraoperatively. Overnight ventilatory support was given for relaxation of brainstem and laryngeal edema. Next morning, she was extubated without new deficit. Neck was supported by hard collar to correct torticollis. She received vigorous physiotherapy. Her left hand’s fingers started moving by the fourth day. She was discharged on the 10th postoperative day. After 1 month, she was moving neck in all directions and had left UL power 3/5 (Medical Research Council score). The collar was continued for 6 weeks. At 6-month follow-up, she can sit, walk, speak clearly, use both ULs with right dominance, and move neck in all directions, but mostly keep tilted right side [Figure 1C and D].

Figure 3

(A) Intraoperative image showing bulging cord lipoma (star marked) with dura (mixed) after dissecting free from subcutaneous lipoma (block marked). (B) Absent C1 arch and maximum bulge was through occiput and C2 lamina. The retractor is retracting the bulge to expose C2 lamina. (C) Multilobulated lipoma, after it was completely dissected free from surroundings. (D) Partial removal of lipoma, and dura was reconstructed to cover the cord. (E) Closure of reconstructed dura.

DISCUSSION

Intramedullary lipoma, which involves both brainstem and spinal cord, is non-dysraphic type.[234567] It is like a benign intramedullary lesion.

After searching PubMed and cross-references, we found total 22 case reports till now.[12,4567891011] Of 22 cases, lipoma was commoner in male, 13 cases. Mostly the lesion was detected before 3 years of age (59% cases) and all cases were detected before 20 years of age. It suggests slow growth of lesion and origin of symptoms due to mass effect, rather than direct damage. The most common symptom was weakness of limbs, in which quadriparesis was commonest (77%). Other symptoms in descending occurrence were incontinence (23%), hypotonia (20%), subcutaneous mass (20%), delayed milestones (14%), respiratory difficulties (14%), spasticity (10%), hydrocephalus (10%), dysphagia (10%), seizures (5%), nystagmus (5%), and pain (5%).[12,4567891011] In our patient, monoplegia, subcutaneous pulsatile mass, and dysphagia were present. The torticollis was altogether different symptom, reported for the first time. The probable reason of torticollis and dysphagia was compression of 9th, 10th, and 11th nerves.

MRI brain–whole spine, T1/T2/fluid-attenuated inversion recovery, is the investigation of choice. It shows complete extension, status of cord, and brainstem. However, it does not give much idea about plane between neural tissue and lipoma. Some functional neural tissues are mixed with lipoma at junction site. That is why complete removal is not feasible and it should not be attempted, also reported by Iplikcioglu and Karabag.[7]

Due to paucity of literature, there is no clear guideline about surgical resection. Le Feuvre et al.[1] reviewed all cases of spinal lipoma with cranial extension till 2004 and based on their case, they suggested that partial decompression and duroplasty, poorer prognosis of intracranial component, and functional improvement might take up to 2 years. Sanli et al.[2] collaborated data of most cases of brainstem–spinal lipoma till 2010. They concluded that the most common symptom was quadriparesis and partial decompression achieved satisfactory outcome.[2] We have reviewed all cases reported till now and complied our data of cases after 2004 in Table 1. On the basis of the literature and our own experience, we recommend few points: (1) The pigmented spots and subcutaneous mass are the markers of underlying lipoma. The incision should be such that it incorporates maximum part of it. (2) The dura must be reconstructed by dissecting it free from subcutaneous fat and intramedullary fat. (3) Wide laminectomy and craniotomy should be carried out to decompress and expose lipoma. (4) Superficial part of lipoma should be resected or aspirated with ultrasonic aspirator. (5) A portion of fat must be left behind. Dissecting fat tangentially can do it. (6) Lax duroplasty is must.

Table 1

Details of brainstem lipoma papers post 2003

S. no.	Author	Year	Age/sex	Lipoma extension	Symptoms	Postoperative outcome	Surgery
1	Kai et al.[8]	2003	8 m/F	Cervical to PCF	Quadriparesis, dysphagia	Satisfactory	Partial resection
2	Le Feuvre et al.[1]	2004	18 y/F	Cervical to PCF	Quadriparesis B–B incontinence	No recovery	Partial resection
3	Naim-ur- Rahman et al.[5]	2006	3 y/F	Dorsal to PCF	Quadriparesis respiratory compromise	Satisfactory	Partial resection
4	Ganapathy et al.[9]	2006	11 y/M	Cervicodorsal junction to PCF	Left UL monoparesis, spasticity both LL	Initial deterioration, then recovery	Partial resection
5	Takatani et al.[11]	2008	10 y/M	Cervical to PCF	Ataxia and paraparesis	Satisfactory	Partial resection
6	Vila Mengual et al.[10]	2009	16 m/M	Cervical to PCF	Hemiparesis	Initially poor outcome followed by recovery	Partial resection
7	Sanli et al.[2]	2010	12 y/F	Dorsal to PCF	Quadriparesis	Satisfactory	Partial resection
8	Iplikcioglu and Karabag [7]	2018	24 y/M	Cervical to PCF	Quadriparesis	Satisfactory	Partial resection

PCF = posterior cranial fossa, B–B = bladder and bowel, m = months, y = years, M = male, F = female, UL = upper limb, LL = lower limbs

Operating such lesion causes significant damage to neck muscles and posterior column of spine. It may cause instability of spine and swan neck deformity. We could not find any reference article about fusion of spine or addressing spinal instability at such young age with extensive lesion. We put bone pieces back and advised hard collar to allow natural fusion and correct torticollis. Our plan is observation of child for the next 5 years for first growth spurt and see progress. If she develops neck deformity, doing instrumentation would be easier with less complications.

The outcome was satisfactory or good in most cases (60%), which attempted partial or subtotal resection.[12,4567891011] The torticollis of our patient improved significantly and her UL regained power.

CONCLUSION

Intramedullary, non-dysraphic lipoma is rare lesion, when it involves both cord and brainstem. It is a benign condition, which presents with both lower cranial nerves and cord symptoms. Overlying skin should be carefully examined for pigmentation and pulsations of lesion. The goal should be decompression, not complete excision. The differentiation between normal parenchyma and lipoma is not possible at junction site. In postoperative period, functional recovery is good, despite extensive involvement.

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Conflicts of interest

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