Giant High-Grade Immature Teratoma of the Central Nervous System (CNS) in an Infant: A Case Report

Background

Teratomas are germ cell tumors of different tissue types and stem from 3 germ layers: ectoderm, mesoderm, and endoderm [1]. These types of neoplasms can be gonadal or extragonadal. The most common site of extragonadal ones is the sacrococcygeal region; however, they can also occur in the neck, orbit, and intracranial regions [2] and affect various loci within the central nervous system [3].

Central nervous system teratomas are cancerous tumors that include mixed and malignant classes [3]. However, they can also be histologically classified as mature or immature based on whether immature neuroectodermal elements are present within the tumor [4]. These neoplastic lesions differ from mature cystic teratomas in that they demonstrate clinically malignant manners, are much scarcer, and affect younger people more than older people [5]. Moreover, they are further classified into 3 grades based on World Health Organization (WHO) 2014 recommendations, which is a 3-degree grading system including “low grade” (grade I) immature teratomas and “high-grade” (grade II and III) ones [6–8]. Although congenital intracranial immature teratomas are extremely rare lesions, they can sometimes grow to sizes big enough cause death and thus require immediate medical attention [2,5].

We present a rare case of a high-grade immature teratoma (grade II) containing both embryonal and adult tissues derived from all 3 germ layers in solid and cystic fashion with immature neuroepithelial elements present in multiple foci.

Case Report

A 16-day-old neonate was referred to Imam Hossein Hospital, a pediatric hospital affiliated with Isfahan University of Medical Sciences, with a giant tumor on the left side of his face (Figure 1A). In prenatal history, the mass was not diagnosed in routine pregnancy ultrasounds until the 36th week, when the radiologist reported a giant mass in the head. The hospital committee suggested abortion, but the parents did not consent. Ten days later, the infant was delivered with a caesarian section, healthy, and an APGAR score of 5. Total medical history showed the patient was otherwise healthy. The initial examination detected no other anomaly except for incomplete retinal vascularization of the eyes, which was planned to be checked in 3 weeks following the initial examination, decided by the ophthalmologist to make sure that the vascularization process has been finalized. His left eye was under pressure due to the mass of the teratoma and required further oculoplastic consult.

The patient underwent resection surgery, which removed the entire teratoma successfully. A V-shaped incision was made through the tumor. Skin and underlying tissue were dissected. The surgeon had an appropriate view of the parietal, frontal, temporal, and occipital lobes. The teratoma had affected multiple loci of the brain’s left hemisphere, including parietal, frontal, temporal, and occipital lobes. The tumoral tissue was totally removed until normal brain tissue was observed. Hemostasis was done, and duraplasty was completed. A drain was placed, and muscle, subcutaneous tissue, and skin were sutured in different layers. The patient was sent to the Intensive Care Unit (ICU) for a few days. Figures 2 and 3 show the tumor involvement in spiral brain CT scans. The specimen, collected during surgery, was then sent for further pathological analysis.

The pathology department reported macroscopic descriptions of the tumor as measuring 10×8.5×6.5 centimeters, solid-cystic in the cut surface, and precise fluid in cystic parts. The cut surface was variegated with soft to hard consistency in different parts, and hair follicles were present in one area. Sections showed a mixture of embryonal and adult tissues derived from all 3 germ layers in solid and cystic fashion. In addition, immature primitive neuroepithelial elements were seen in multiple foci (Figure 4).

Except for the retinal vascularization of the left eye, which was also completed in the second visit, no other problem was detected in the history or observed in the physical examination. Thus, it was the result of an examination both before and after the surgery. Also, a slight hearing loss in the left ear was detected, which did not progress over time.

The patient did not require chemoradiotherapy according to our oncologist. Serum levels of hormones, including alpha-fetoprotein (αFP), were not much higher than normal in multiple follow-up measurements. The patient has been followed up for 1 year. The follow-up reports show normal serum markers. On day 30 of life, the value of AFP was 300 IU/ml according to chemiluminescent immunoassay (CLIA) method, which is normally up to 100 000 IU/ml at this age. On day 90 of life, the value was 830 IU/ml, normally up to 60 000 IU/ml with the CLIA method. The patient was also examined in a one-year post-surgery visit, and the value of AFP was 0.29 IU/ml, which is also in the normal range. In immature teratoma, chemoradiotherapy is necessary if complete resection has not been done or serum αFP is higher than normal [3]. All clinical manifestations as well as development of motor and sensory functions were within normal limits. The patient only has some decreased visual acuity of the left eye and slight hearing problem in his left ear, which was found after age 1 year and did not progress (Figure 1B).

Discussion

Teratomas are among the most common congenital central nervous system (CNS) tumors [9,10]. They can arise in different locations within the CNS, including the midline, cerebral hemispheres, the third ventricle [11,12], and less often in basal ganglia and cerebellopontine angle [13].

Generally, teratomas are categorized into 2 subtypes: mature and immature. Mature teratomas are considered benign tumors that can be cystic or solid, consisting of well-differentiated adult tissues from one or more germ cell layers [8,9]. Immature teratomas, on the other hand, are malignant tumors. They possess mature elements from one or more cell layers and immature elements, mainly neuroectodermal. Mature teratomas are reportedly more common than immature ones and immature congenital teratomas are considered extremely rare lesions. [5,8,10]. However, our case deviated from the norms mentioned earlier, as it occurred in the left hemisphere of the brain, involving temporal, parietal, and occipital brain lobes, and was far from the midline. The tumor demonstrated both embryonal and adult tissues derived from all 3 germ layers in solid and cystic fashion, with immature neuroepithelial elements present in multiple foci.

The literature on immature teratomas, particularly enormous ones, is limited. Sawamura et al reported the largest case series of CNS teratomas, with a sample size of 34, among which only 7 cases were immature [11,12].

Although the paper that Sharifi et al, published in 2016, reported a case with somewhat similar local characteristics to our patient’s teratoma [2], our case is unique as it did not require chemoradiotherapy after 1 year of follow-up and was resolved after surgery. Note that the prognosis of congenital intracranial teratomas is tremendously poor, as the mortality rate is around 90% [13,14].

Given the prevalence of congenital immature teratomas and, paradoxically, the rarity of immature ones among all tumors, in addition to the importance of early diagnosis and treatment, every piece of evidence on these tumors is considered worth reporting [11,12]. Reports have mostly been of cases of mid-line teratomas, but our paper presents one situated far from the midline. The fact that teratomas can occur in sites other than the midline should be considered in the differential diagnosis by clinicians [3,5,10]. More cases like this presentation need to be reported to better understand the etiopatho-genesis of extragonadal teratomas developing in sites other than the midline.

Conclusions

Early diagnosis and treatment of immature teratomas are essential for patient prognosis. Chemotherapy is not always needed, but complete surgical removal and patient follow-up are always a necessity. Follow-up of these patients is extremely important to evaluate their further treatment plan. Recurrence of these rare tumors should always be considered, and sufficient follow-up is of utmost importance [15]. In developing countries, patient follow-up and data registry are much worse than in developed countries. Patient follow-up for detecting recurrence is much more complicated and is usually missed.