Sacrococcygeal tumours in children.
Sacrococcygeal region is the seat of frequent developmental anomalies and a favoured site for germ cell tumours in the paediatric age group. The germ cell tumours located at sacrococcyx differ from similar tumours of other organs in their age and sex distribution, association with congenital malformations, and the incidence of malignancy in relation to the age of the children.,,,,,,,,, While several tumour registries from West have described various clinicopathologic features of Sacrococcygeal teratomas, there is scarcity of reports from the Eastern hemisphere especially India which has a different geographic and socioeconomic background. The present communication gives a comprehensive account of certain clinical and pathological features of Sacrococcygeal swellings as seen in Varanasi.
From January 1962 upto December 1982, a total of 60 specimens from sacrococcygeal region in children upto 15 years of age were registered in the files of the Pathology Department, Institute of Medical Sciences, Banaras Hindu University. The data of these children was analysed with regard to their age, sex, and gross and microscopic pathology. The sacrococcygeal teratomas were classified according to Valdiserri and Yunis into three groups. (1) benign teratoma which contained only mature tissue; (2) immature teratoma showing mature as well as significant amount of immature elements, and (3) malignant teratoma exhibiting frankly malignant tissue along with mature and/or immature components. A minimum of four haematoxylin and eosin stained sections were available for study in each case.
Histologically, 41 tumours (68%) were of germ cell origin, 16 (27%) meningoceles or meningomyeloceles and three cases (5%) were of hamartomas. In the germ cell group, 31 were benign, five immature and the remaining five cases were malignant. The age and sex in various histologic groups is shown in [Table 1]. The age was recorded in 55 children only and it ranged between 3 days and 15 years. A total of 48 patients (87.2%) came in the first quinquennium, four (7.3%) in the 2nd and three (5.5%) in the 3rd quinquennium. Further analysis of 48 patients within the first quinquennium revealed eleven children to be upto first month of age, 28 between 2nd and 12 months and 9 within 13 to 24 months. All cases of meningocele, 66.6% of hamartomas and 55.5% of germ cell tumours came during the first year of life. The incidence of malignancy was 5% in children seen upto the first year and 25% in those who were more than one year of age.
In all, 39 were boys and 21 girls. The M : F ratio in benign cystic teratoma was 18:13, immature teratoma 3:2, malignant teratoma 1:4, meningomyelocele 15:1 and hamartoma 2:1.
The biggest diameter in germ cell tumours ranged between 1.5 and 21 cm and in meningocele and hamartomas between 1 and 10 cm [Table 2]. On an average, the hamartomas were the smallest and the immature teratomas, the largest in size. There was no correlation between the age of the patient and the size of the tumour.
The benign teratomas were predominantly cystic in 26 cases (93%), and solid in two cases (7%). All the cases of immature teratomas were partly solid and partly cystic, and in malignant teratomas three (60%) were solid and two (40%) showed both solid and cystic areas. The hamartomas were soft solid masses, and all the meningocoele were cystic.
The organized structures resembling normal mature tissue were seen in 16 (51.6%) benign, 4 (80%) immature and one (20%) of malignant germ cell tumours. The cartilage was the only component in 9 cases (8 benign and one malignant), bone in 6 cases (4 benign and 2 immature), both bone and cartilage in 5 cases (4 benign and one immature) and rudimentary intestine and digit in a single case of immature teratoma. In combination with cartilage and bone, well formed tooth and sebaceous material were seen in one case each of benign teratoma. The mean age of children whose tumours showed organized structures was 30 months in benign, 37 months in immature and 88 months in malignant germ cell tumours in contrast to 20, 28 and 50 months respectively of those whose tumours did not reveal organized structure. The biggest diameter of tumours having organized structures was 10 cm in benign, 13 cm in immature and 10 cm in malignant teratoma as compared to 7.5 cm, 11 cm and 5 cm respectively of those tumours which were without organized structure.
Benign teratomas showed tissues derived from all the three germ layers. The ectoderm al elements were the principal constituents comprising stratified squamous epithelium in 85 per cent and skin appendages in 52 per cent. The neural and central nervous system tissues were the next common and formed the main bulk of the tumour in three cases. Nerve bundles were seen in 72 per cent, glial tissue 62 per cent, ventricle with choroid plexus in 17 per cent and ganglion cell clumps in 17 per cent cases. The endodermal derived tissue was seen in 70 per cent and included cuboidal, columnar and endothelium lined cystic spaces of varying sizes and shapes. The mesodermal components included fat in 62 per cent, striated and smooth muscle fibres in 52 per cent, cartilage in 55 per cent, bone in 48 per cent, lymphoid follicle with or without germinal centre in 34 per cent and haemopoietic elements in 14 per cent of tumours.
Besides the haphazard distribution of above tissue elements, the organized respiratory epithelium in association with cartilage and smooth muscles was seen in 55 per cent intestinal mucosae along with smooth muscles and some times myenteric plexus in 45 per cent, retinal analgae in 10 per cent, salivary gland with acini and ducts in 7 per cent and renal tubules, pancreatic tissue and adrenal cortical components in one case each.
All cases of immature teratoma showed predominantly immature embryonic tissue. The embryonic component included neuro-epithelial elements with well formed rosettes, and loose primitive mesenchymal tissue in 4 cases, renal blastoma in 3, and precartilage in one case.
The malignant teratoma was of squamous cell origin in one, adenocarcinoma in one, undifferentiated sarcoma in one, neuro-blastoma in one and endodermal sinus tumour in one. The immature elements were seen in all and mature tissue in one case only.
The cyst lining of the meningocele was mainly fibro-collagenous and nerve elements were seen in six cases.
The hamartomas showed fibromatous and lipomatous tissue in varying proportions.
A total of one hundred and thirty five paediatric age germ cell tumours were seen during the study period and of these, 41(30%) were located in sacrococcyx. This incidence is higher than that reported by Marsden et al, but lower than other large series,, in which 44-64% of germ cell tumours were seen in this region. More than 90 per cent cases of developmental anomalies (meningocele and hamartoma) and 54% of germ cell tumours were seen in males whereas in all other reports females outnumbered the males. The females accounted for 61 to 83 per cent of sacrococcygeal tumours.,,,,,,, The relative male predominance in hospital-based study at this centre indicate socio-economic factors in favour of male population.
The presenting age in sacrococcygeal germ cell tumours in the present series was higher in comparison to others and only 8.3 per cent children came within one month whereas in other reported series,, 62 to 85 per cent cases of sacrococcygeal germ cell tumours presented with in the first month of life. Mahour et al found 72.2% of sacrococcygeal tumours at the time of birth. The incidence of malignancy was five times more in children who came after first year of life as compared to those who came upto one year and this is in agreement with other reports., Berry et al observed malignancy rate of 33.3% in tumours seen after 1 year of life as compared to none at or before one year of age. Donnellan and Swensen reported 91.7% malignancy in infants over 2 months of age. This consistency in the present findings with all other reports emphasizes that malignancy in sacrococcygeal teratomas increases with the advancing age of the child and the tumour should be excised at the first opportunity.
The incidence of benign, immature and malignant sacrococcygeal teratomas in the present series is comparable with other reports,,,,, [Table 3]. However, the malignant germ cell tumours at sacrococcyx were of heterogenous group and only one out of five was of squamous cell type whereas in ovaries most of the malignant teratomas are known to be of squamous cell origin. Donnellan and Swensen have also emphasized the heterogenity of malignant teratoma at sacrococcyx and reported 30% of malignant teratomas to be of glandular origin.
The malignant tumours were the smallest in size and the immature teratoma the largest and this is in confirmity with others. Smaller tumours have greater chances of malignancy than the larger. This probably may be due to the fact that malignancy leads to early and more serious metabolic aberrations, constitutional symptoms and change in internal milieu, thus compelling the patient to report to the hospital at a stage when it has not acquired a very large size.
The mean age of the children whose tumours showed organized structures and also the size of these tumours were higher as compared to the mean age and size of sacrococcygeal tumours without organized structures. Probably the maturation of the tissue (organogenesis) is related with the duration of lesion and the maturity of child.