<unk>  was first described by Stanley in 1842. In 1863, first successful surgery was performed on<unk>  by Dr. W. Blizard. Between 1950s and 1960s, germ cell theory of the origin of<unk>  was introduced.<unk>  is one of the most common congenital tumors. The incidence of<unk>  is estimated to be 1 in 35,000 births.<unk>  is classified into four different categories according to American Academy of Pediatrics Surgery classification based upon the anatomical location of the tumor. Subtypes of<unk>  have different staging systems based on the size and growth of the tumor, lymph node involvement, and the presence of metastasis.<unk>  originates from the pluripotent cells in primitive knot or Hensen's node, which is the primary organizer of embryonic development, located on the anterior surface of the sacrum or coccyx by 2rd or 3rd gestational week. Development of<unk>  is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions. The pathophysiology of<unk>  depends on the histological subtype. Development of<unk>  is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions.<unk>  must be differentiated from endodermal sinus tumor, ependymoma, fibromatosis, ganglioneuroma, giant cell tumor of the sacrum, leiomyoma, meningomyelocele, ovarian<unk> , neuroblastoma, retrorectal hamartoma, intracanalicular epidermoid tumor, rhabdomyosarcoma, paraganglioma, dermal sinus stalk ascending towards the conus modulars, and hydromelia. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for<unk> a<unk> . The hallmark of<unk>  is a protruding mass at the<unk>  region. It is important to obtain the history about the onset, and the progression of the symptoms. Most common symptoms of<unk>  are due to compression caused by the large tumor mass. Patient with<unk>  usually are generally well-appearanceing. Physical examination of patients with<unk>  is usually remarkable for a protruding pre sacral mass. Alpha-Fetoprotein and beta-hCG should be evaluated in patients with<unk>  to determine the presence of malignant component of the tumor. On x-ray,<unk>  is characterized by a large mass projecting from the lower pelvic region or within the abdominopelvic cavity. CT scan is not part of the routine investigation of<unk> . On CT scan,<unk>  is characterized by bone, fat, and cystic components. Ultrasound is used to diagnose<unk>  in second trimester. Mature<unk> s tend to be cystic, showing anechoic component. Immature<unk> s are much rare and solid type, showing echogenic mass within the pelvis. Echocardiography identifies high output cardiac state preceding hydrops fetalis. Colour Doppler studies in<unk>  may show marked hypervascularity with arterio-venous (AV) shunting. There is no medical treatment for<unk> ; the mainstay of therapy is surgical. Perinatal surgical intervention is used to decrease cardiovascular complications caused by the large<unk> . Early complete resection is the mainstay of management of benign tumor. Complete surgical excision in malignant<unk>  is followed by platinum based chemotherapy. Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. Most of the<unk> s are benign in nature and prognosis is generally regarded as good after resection. The<unk>  with cystic morphology is associated with the most favorable prognosis.
Sacrococcygeal teratoma
Pineal yolk sac tumor
Gonadoblastoma
Pineal gland cyst
Scrotal cyst
Epididymal head cyst
Chordoma
Hydrocele testis