Is it the Monster "Teratoma" or Simply Meningomyelocele: Our Experience of "Histological Surprise".

Teratomas are one of the most common tumors in newborn with excellent prognosis arises from totipotent primordial germ cells harboring two or three germ cell layers. The tumor has been titled "Great masquerade." The teratomas of sacrococcygeal region present with lower limb weakness, urinary or bowel obstruction, and swelling at lower back or intrauterine mass in ultrasound or complicated delivery. A 2-month-old male child presented with complaints of swelling over lumbosacral region with discharging punctum since birth. Sagittal T2-weighted magnetic resonance imaging (MRI) of the spine showed myelocele at L5 level forming placode with central defect at L4-S1 and low-lying tethered cord up to L4-L5. The patient was operated, and histopathology surprisingly came to be mature teratoma. We followed the patient with serum beta human chorionic gonadotropin and alpha-fetoprotein markers and MRI. Literature supports complete surgical removal, including coccyx and tumor base. Mature teratoma is considered as benign disease thus even subtotal excision is appropriate but with aggressive follow-up. The difference in recurrence following total compared to subtotal resection is considered insignificant. In this article, we have discussed the management of teratoma in detail. Teratoma with meningomyelocele is a rare entity. There is still dilemma in managing cases and prognosticating parents in such patients. The provisional diagnosis of teratoma should also be considered when child presents as midline sacrococcygeal mass.

INTRODUCTION

Spinal teratomas among dysraphism with excellent prognosis, and arises from totipotent primordial germ cells harbouring two or three germ cell layers. In this article we are reporting management dilemmas of both benign and malignant teratoma.

CASE REPORT

A 2-month-old male child presented with complaints of swelling over lumbosacral region with discharging punctum since birth. The swelling has progressively increased in size with no history to suggest paraparesis or bowel/bladder involvement. On examination, a 3 cm × 4 cm in size, soft, spherical swelling with a discharging punctum (whitish, nonfoul smelling), and intact skin was seen involving lumbosacral region in midline. There was no palpable bony defect. Anterior fontanelle was patent and lax.

Radiology

Sagittal T2-weighted magnetic resonance imaging (MRI) of spine showed myelocele at L5 level forming placode with central defect at L4-S1 and low-lying tethered cord up to L4–L5 [Figure 1]. Screening whole spine MRI revealed cervico-dorsal syrinx suggestive of tethering with lipoma from L2 to S1.

Figure 1

Sagittal T2-weighted magnetic resonance imaging of spine showed myelocele at L5 level forming placode with central defect at L4-S1 and low-lying tethered cord up to L4–L5. Screening whole spine magnetic resonance imaging revealed cervico-dorsal syrinx suggestive of tethering with lipoma from L2-S1

Surgical operation

The patient underwent L2 laminectomy, the thecal sac was identified and opened. The lipoma present dorsally on the cord extending into placode was inspected, debulking of placode was done, and raw areas were sutured. The thickened filum terminale was coagulated and cut. Histopathological examination revealed neural tissue admixed with squamous epithelium along with cartilage. Focal areas of sebaceous gland and adipose tissue were also seen suggestive of mature teratoma. Follow-up MRI showed no residual tumor, and serum alpha-fetoprotein (AFP) and beta human chorionic gonadotropin (HCG) levels are normal.

DISCUSSION

Teratomas are one of the most common tumors in newborn with excellent prognosis. Teratoma arises from totipotent primordial germ cells harboring two or three germ cell layers. Koen et al. in their theory explain origin from remnants of primitive streak and Hensen node. These remnants aggregate in caudal region of developing spine to form mass. This theory explains the association of myelomeningocoele and teratoma as a common origin can give rise to both conditions through incomplete fusion of structures.[1] These tumors possess potential to transform into malignant mass commonly as squamous cell carcinoma.

The tumor has been titled “Great masquerade.” Overall, sacrococcygeal teratoma is the most common site with incidence of 35%–60% of overall teratomas.[2] A large number of pleuripotent stem cells in caudal region of embryo may be the reason for sacrococcygeal region being the common site.

Epidemiology

Teratoma is seen in 1:35,000 live births.[3] The disease more commonly afflicts females worldwide, but a study from India suggests equal sex distribution.

Clinical features

The teratomas of sacrococcygeal region present with lower limb weakness, urinary or bowel obstruction, and swelling at lower back or intrauterine mass in ultrasound or complicated delivery. The long-term incontinence of urine and stool is a common persisting complaint. The most common mode of presentation seen is swelling at lower back region. The teratomas presenting as mass in sacrococcygeal region requires differentiation between teratoma and meningomyelocele as both may have a similar presentation.[4] Jan et al. has reviewed all causes of delay in diagnosis and poor outcome of teratomas and found that 5 out of 12 patients presented as MMC. Similarly, Sugitani et al. reported the case of teratoma mimicking MMC.[5] Sharma and Jain in their study studied 27 patients of teratoma, out of which seven patients were misdiagnosed as MMC.[6] The midline spinal hamartomas are unusually associated with hydrocephalus, Chiari malformations, or open spinal dysraphisms.[7] Thus, early differentiation of this entity among others causes of back swelling [Table 1] and particularly from MMC is imperative to achieve a good outcome.

Table 1

Differential features of teratoma from myelomeningocele

Investigation

MRI forms the major investigation tool for both spinal teratomas and spinal dysraphism. Rectal examination is also important, especially in cases where no neurological deficit is seen, and diagnostic dilemma exists between MMC and teratoma.

Histopathology

A teratoma on histopathological examination may be reported as mature or immature [Table 2]. Mature teratomas can be classified as solid or cystic (dermoid cysts). A dermoid cyst is lined with epithelium that contains tissues and cells normally present in the skin layer, including hair follicles and sebaceous and sweat glands.[8] Teratomas are graded on the basis of percentage of immature tissue in histopathology sections.

Table 2

Gonzalez-Crussi histopathologic grading

Treatment

Teratomas are histologically classified as immature or mature depending on the degree of differentiation of their cellular constituents. Literature supports complete surgical removal, including coccyx and tumor base.[9] Mature teratoma is considered as benign disease thus even subtotal excision is appropriate but with aggressive follow-up. The difference in recurrence following total compared to subtotal resection is considered insignificant. The reason behind recurrence is the totipotent cells in teratoma tissue. Jouannic et al. show recurrence rate as high as 37% if complete excision including coccyx is not done.[10] Jillian and Elizabeth in their 5-year follow-up and Altman et al. in their one of the largest series of teratoma patients have given various determinants of recurrences. These include age at the diagnosis and treatment and the extent of resection, histologic type, and stage at the time of resection. He also proved that size of the tumor does not determine the prognosis.[11] Some authors believe that chemotherapy and radiotherapy should be offered for recurrent or residual lesions. Patients with incomplete excision may be offered adjuvant therapy for malignant tumor. Jillian and Ellizabeth followed patients with complete or incomplete excision and found no difference in terms of overall survival whether adjuvant therapy was given or not. In their 5 years follow-up, they reported survival rates of 92.2% and 85.9%, respectively.[12] When treating immature teratomas, the additive benefit of radiation and chemotherapy is yet to be justified.

There are no guidelines as such for the management of histological surprises as in our case. In previous reports where immature teratoma was histopathology consideration to follow-up was given. We also believe that immature teratomas should be followed up both radiologically and with serum markers. Management of immature teratomas is controversial. Factors such as age of patient, anesthetic fitness for the second surgery, possibility of lost to follow-up especially in the Indian scenario, status of margins of tumor, and expected survival [Figure 2]. There is no evidence for advantage of radiotherapy or chemotherapy, but threshold should be low.

Figure 2

Management of teratoma postexcision of swelling thinking it to be MMC

Follow-up

Patients of teratomas are usually followed up with AFP (serum) and beta HCG markers. Their role in follow-up is well established in literature. Follow-up MRI although not necessary does help in early diagnosis of recurrence.

CONCLUSION

Teratoma with meningomyelocele is a rare entity. There is still dilemma in managing cases and prognosticating parents in such patients. The provisional diagnosis of teratoma should also be considered when child presents as midline sacrococcygeal mass. High suspicion and low threshold for serum markers can change life expectancy and need for second surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.