PEDIATRIC SURGERY UPDATE ©
VOLUME 47, 2016

PSU Volume 47 No 01 JULY 2016

Paratesticular Rhabdomyosarcoma

Wilms Tumor: Intracaval Extension

Wilms tumor also known as nephroblastoma is the most common malignant renal tumor in children. The survival rate of Wilms tumor has improved significantly over the years to better than 90% long-term survival with the use of surgery, chemotherapy and in a few instances radiotherapy.  Large size of tumor, involvement of adjacent vital structures and intracaval tumor thrombus are universal accepted inoperable criteria. Wilms tumor has a strong tendency to invade blood vessels in the form of tumor thrombus into the renal veins, inferior vena cava and right atrium. Extension of tumor thrombus along to the renal veins into the inferior vena cava occurs in 4-10% of all children, while intraatrial extension occurs in 1-3%. Intracaval extension has been reported to be more common in the right kidney due to a short anatomic renal vein. Most cases with intracaval extension of tumor are asymptomatic and the diagnosis is made during imaging workup (Ultrasound with Doppler, CT-Scan or MRI). Preop identification of intracaval extension is important for surgery, since removal of the tumor can cause significant bleeding and/or tumor embolization with acute cardiac decompensation or arrest after manipulation of the thrombus if it's not adhered to the vessel wall. Staging the extension includes: Level 1-infrahepatic extension < 5 cm, Level 2 - intrahepatic extension > 5 cm and Level 3 - suprahepatic or Level 4 - atrial extension. Identification of intracaval tumor extension should ideally be managed with preoperative chemotherapy prior to resection to reduce the anticipated surgical risks. Preop chemotherapy reduces size of the tumor, dissolute the thrombus and provides easy surgical removal. This approach can avoid but nor eliminate the need of cardio-pulmonary bypass and cavotomy during removal of the tumor. Failure of regression, failure to tolerate chemotherapy or acute tumor rupture may need early resection. Single best predictor of survival is the histologic subtype.   

Urticaria Pigmentosa

Urticaria pigmentosa (UP)falls into the classification of disorders known as pediatric maculopapular cutaneous mastocytosis. Most cases occur in white patients with lesions occurring before the age of two years in the majority of cases. Urticaria pigmentosa is associated with mutation in the signaling receptor molecule c-KIT. UP can appear as a generalized maculopapular rash in the trunk and proximal extremities or as a mastocytoma single lesion large tan-orange plaque or nodule. With mechanical irritation of the plaque or nodule histamine, leukotriene and prostaglandin is release from mast cells causing the symptoms of urticaria (Darier's sign). The diffuse form has an indolent benign course. Diagnosis of urticaria pigmentosa is clinical. Biopsy is rarely necessary but is definitive and may be performed in cases where the diagnosis is not certain based on clinical features or the child is having constant irritation of the lesion with frequent signs of urticaria and pain. Histopathological diagnosis is made by observing mast cells showing metachromasia with toluidin blue in full-thickness skin biopsy. Main management of the systemic form of the disease consist of long acting oral H1- antihistamines. Persistently symptomatic mastocytomas or blistered or ulcerated lesions may be treated with high-potency topical glucocorticoids under occlusion or surgical excision if deemed necessary. The prognosis in most cases is excellent.

PSU Volume 47 No 02 AUGUST

Chylous Mesenteric Cyst

Patent Processus Vaginalis

Meckel Diverticulitis

PSU Volume 47 NO 03 SEPTEMBER 2016

Vascular complications of CVC

Pneumoscrotum

Pneumoscrotum is very rare and refers to the presence of gas within the scrotal sac of males. Pneumoscrotum includes scrotal emphysema as well as pneumatocele. Scrotal emphysema is palpable and shows signs of scrotal swelling and crepitus, while pneumatocele is not palpable because the air present within the tunica vaginalis of the testis. There are three ways to explain the presence of air in the scrotum: subcutaneous or retroperitoneal air that dissects into the Dartos lining of the scrotal wall, local gas production (gas gangrene) or air introduction, and movement of air from the intraperitoneal space into the scrotum. As such the etiology of pneumoscrotum can include pneumomediastinum, tension pneumothorax from thoracic trauma or spontaneous, pneumoperitoneum, Fournier gangrene, bowel perforation from instrumentation such as colonoscopy, spontaneous or sick bowel. Traumatic and iatrogenic causes accounts for most cases of pneumoscrotum. Endoscopic colonic procedures and abdominal endoscopy accounts are the main causes of iatrogenic pneumoscrotum. Newborns present a high incidence of pneumoscrotum due to gastric and bowel perforation. Causes are various:  congestion of the bowel wall secondary to asphyxia or septicemia, trauma coincident with delivery, excessive gastric acidity, direct or indirect mechanical injury from gavage tubes or resuscitation maneuver, congenital mural defects of the gastroenteric tract, meconium stasis, rupture of a diverticulum, and coincident central nervous system abnormalities. Most clinical pneumoscrotum follows a benign course and can be managed conservatively with observation and antibiotics. Nonsurgical treatment is chosen because of the delayed presentation, lack of abdominal and perineal pain and clinical stability of the patient.

Hyalinizing Trabecular Thyroid Tumor

Hyalinizing trabecular tumor (HTT) is a rare and controversial tumor of the thyroid gland with uncertain malignant potential frequently misdiagnosed and managed as other thyroid neoplasm due to the similar morphology mimicking papillary thyroid carcinoma and medullary thyroid carcinoma.  Some pathologists believe that HTT is a variant of papillary thyroid carcinoma while others believe it to be an independent neoplasm. HTT has a characteristic trabecular growth pattern and hyalinizing stroma. The overwhelming majority of HTT behaves as benign neoplasms. Malignant potential occurs when there is vascular, capsular and/or parenchymal invasion, local recurrence or distant metastasis. The problem aggravates when FNA is utilized since the features of hypercellularity and grooves, pseudoinclusions and hyperchromaticity of the nuclei which are the main diagnostic features of HTT can also be observed in patients with classic papillary carcinoma. US features of HTT are marked hypoechogenicity, absence of calcifications, parallel shape and presence of vascularity. Surgeons should be aware that the preoperative cytological or frozen section diagnosis may not necessarily agree with the final pathological diagnosis due to the overlapping nature between HTT and PTC. Frozen section is not always diagnostic of HTT. This difficulty with the pathologic diagnosis using FNA can result in overtreatment of a universally benign disease. This overtreatment can occur in 44-71% of patients harboring a HTT.  HTT arises in glands that harbor chronic Hashimoto thyroiditis and multinodular goiter. Grossly HTT are well circumscribe or encapsulated with a color ranging from yellow to tan. It is recommended to perform immunohistochemical stains, at least Ki-67 and Cytokeratin-19 reaction to correctly identified HTT. The prognosis of HTT is excellent and management should consist of thyroidectomy of the affected gland lobe alone.

PSU Volume 47 NO 04 OCTOBER 2016

Prepubertal Testicular Tumors

Prenatal Diagnosis Esophageal Atresia

Esophageal atresia (EA) with or without tracheoesophageal fistula is the most common congenital anomaly of the esophagus in children. Prenatal diagnosis of EA relies on the indirect findings in routine sonography at 16-20 weeks gestation of a small or non-visualized stomach bubble in conjunction with subsequent maternal polyhydramnios after 24 weeks. These US findings are nonspecific and can be transient in nature creating unnecessary anxiety in the expectant mother and relatives. Two other more direct signs of the US diagnosis of EA include a dilated proximal esophageal pouch (upper pouch sign) and failure to visualize the entire thoracic esophagus. Using all these findings in US the rate of diagnosing  EA prenatally occurs one-third of the cases. Most cases of EA that are diagnosed prenatally are the long-gap esophageal variety without tracheoesophageal fistula which occur with an overall incidence of 8%. The most common variant of EA with distal tracheoesophageal fistula is missed most of the time since it decompresses through the fistulous tract into the stomach and filling it preventing the development of polyhydramnios. Prenatal diagnosis of EA gives us the opportunity for optimal perinatal management with delivery of the fetus in a tertiary care pediatric center with expertise in esophageal surgery.  Fetal MRI and biochemistry of the amniotic fluid can help confirm the diagnosis since gamma glutamyl transpeptidase (GGTP) and alpha-protein (AFP) in amniotic fluid are elevated in EA. The dynamic sequence of MRI during fetal swallowing is needed to increase the diagnostic yield. Since 50% of EA children have an associated malformation these must be looked carefully to correlate with the diagnosis of VACTERL, CHARGE, abnormal karyotype or other associated syndromes dictating prognosis.

Aberrant Subclavian Artery

Aberrant subclavian artery, also known as arteria lusoria, is the most common form of aortic arch vascular anomaly. It results from regression of the right 4th aortic arch between the carotid and subclavian arteries. The right subclavian artery usually persists as a branch from the descending aorta distal to the takeoff of the left subclavian artery and coursing posterior to the esophagus, though it can also pass between the esophagus and the trachea or even anterior to the trachea very rarely. Patients with an aberrant subclavian artery can develop symptoms which include dysphagia, cough, stridor, regurgitation, asphyxia induced by feeding, a globus sensation (or lump in the throat), failure to thrive and thoracic pain, though most patients with this anomaly remain asymptomatic throughout their lifetime. Infants can present with respiratory symptoms due to dysphagia and aspiration of food particles. Some asymptomatic patients can elicit symptoms during exercise. Barium swallow imaging shows a characteristic diagonal posterior compression defect at the level of the 3rd and 4th vertebrae which is diagnostic. CT or MRI angiography and transthoracic echocardiogram confirms the diagnosis. Symptomatic children should undergo surgical management. The goal of operative repair is relieving the symptoms and restores circulation. This is done by reimplanting the aberrant subclavian artery into the ascending aorta or the right common carotid artery directly through a right thoracotomy in children. Anatomic variations that are associated with an aberrant subclavian artery include abnormal origin of the right vertebral artery from the aorta or from the right common carotid artery, the presence of a c common carotid trunk, a right-sided thoracic duct and a nonrecurrent laryngeal nerve.   

PSU Volume 47 NO 05 NOVEMBER 2016

Toxoplasma Lymphadenitis

Enlarged lymph nodes are a common problem seen in children of all ages. Lymphadenitis commonly represent a transient response to a benign local or generalized infection. The most common causes of subacute or chronic lymphadenitis in children include cat scratch disease, mycobacterial infection and toxoplasmosis. The diagnostic approach to a child with an adenopathy longer than six weeks includes serological assays, radiological studies (ultrasound), fine needle aspiration and most helpful complete excisional lymph node biopsy to establish a histologic diagnosis of malignancy or infection. Infestation with Toxoplasma gondii occurs frequently in children around the world. In immunocompetent host, toxoplasma primary infection produces little symptoms, is self-limiting and has a favorable prognosis without treatment. Less than 10% of infected children are symptomatic, with lymphadenopathy as the most frequent clinical manifestation. Symptoms associated with toxoplasmosis include asthenia, fever and nonspecific such as headache, myalgia or arthralgia. Acute lymphadenopathy usually occurs in the head and neck region, followed by supraclavicular, and inguinal sites. The lymph node is painless, solitary, not matted, with mild inflammation and do not suppurate. Toxoplasma lymphadenitis is most often diagnosed by lymph node biopsy and/or serological assays. Fine needle aspiration is rarely useful for the diagnosis since it does not permit evaluation of lymph node architecture. A negative Sabin-Feldman dye test in a lymphadenopathy with more than three weeks evolution excludes toxoplasma as an etiologic agent. The Sabin-Feldman dye and IgM-ISAGA tests is positive in most patients with toxoplasmosis within the first three months after infestation. Observation is all needed for single toxoplasma lymphadenitis. Co-trimoxazole (TSM) is a good therapeutic agent for cerebral or ocular toxoplasmosis. 

Electrocautery Injury

Bovie designed the first surgical diathermy machine in 1928 to facilitate tumor removal and hemostasis in neurosurgery. The electrocautery involves the passage of electrical current through the body to burn the tissue at the active electrode tip. The current (or flow of electrons) excites tissue molecules producing heat. For cutting intracellular water boils, cells explode and tissue divides. At lower temperatures the heat causes dell dying and blood protein is coagulated causing hemostasis. There are two diathermy modes: monopolar and bipolar. In monopolar the current enters the patient through the small area active electrode and exits safely through the large area neutral grounding pad electrode. This circuit can cause unintended high frequency current burn injury to the patient if not used properly. Bipolar diathermy is safer than monopolar as the current passes between the two prongs of the electrode without significant flow through the patient. A neutral electrode is not required. Advantage of bipolar diathermy is reduction of tissue damage. Electrocautery injury can occur in the form of burn, electrocution, operating room fire, smoke inhalation and gene mutation. Iatrogenic cautery burns can occur from direct contact to the active electrode resting on the patient skin, burns at the site of the grounding electrode, burns from electrode heating of pooled solutions such as spirits, and burns outside the operative field due to an alternate grounding source. Most burns occur due to faulty application of the grounding pad failing to have good contact with the patient skin. An electrocautery injury is a medical error that has medicolegal and ethical implications. The improper use of energy devices may increase patient morbidity and mortality.   

PSU Volume 47 No 06 DECEMBER 2016

Undrained Traumatic Hemothorax

Growing Teratoma Syndrome

Ovarian or testicular teratomas are either mature (most commonly), immature or malignant. The immature and malignant teratomas can secrete alpha fetoprotein (AFP) and/or human chorionic gonadotropin (HCG). Immature teratomas are potentially malignant and as such will need chemotherapy to change the features of immaturity into mature teratoma and reduce the level of tumor markers. Teratomas that increase in size during or after chemotherapy as tumor marker levels decrease is known as growing teratoma syndrome (GTS). By definition GTS includes normalization of previously elevated serum tumors markers (AFP or HCG), an increase in tumor size during or after chemotherapy given for non-seminomatous germ cell tumor and an absence of such components other than mature teratoma at resection. GTS is characterized by an absence of malignant germ cell components as the growing tissue is benign. Further chemotherapy is unable to shrink GTS. The radiological features include increased density of mass with well-circumscribed margins, onset of internal calcification with fatty areas and cystic changes. Retroperitoneum is the most common site for GTS. Pathogenesis of development of GTS is either malignant cell differentiation into mature teratoma or selective chemotherapy induced destruction of immature elements. Complete surgical excision of the mass is required to avoid pressure effects and potential malignant transformation to either sarcoma or carcinoma. Pressure effect of the growing tumor includes vascular thrombosis, ureteral obstruction, bowel obstruction, bile duct obstruction and fecal fistula. Malignant transformation to sarcoma, adenocarcinoma or PNET is reported in 3% of cases. Alpha-2-Interferon can control disseminated unresectable GTS by inhibiting tumor angiogenesis mediated by decreased level of vascular endothelial growth factor and basic fibroblast growth factor, but the regression is slow, incomplete and discontinuation results in progression of disease. Prognosis after complete surgical resection is excellent.

Epiploic Appendagitis

Epiploic appendages are peritoneum-covered fat outpouches protruding from  the serosal antimesenteric border of the taeniae of the large bowel, except in the rectum. Blood supply of the epiploic appendages is derived from a single artery and vein located within the pedicle. Epiploic appendagitis occur when there occurs either torsion and/or infarction of the appendage. Epiploic appendagitis is an uncommon cause of acute abdominal pain in children and adults manifesting most commonly in the fourth or fifth decade of life with male predominance. Mostly epiploic appendagitis involve the sigmoid colon and the pain can be mistaken for diverticulitis. When it involves the cecum it can mimics appendicitis. With the widespread use of CT-Scan in the diagnosis of abdominal pain in children, epiploic appendagitis is commonly diagnosed before operation is undertaken for an acute abdomen. In US the appendagitis shows a noncompressible hyperechoic mass near the colonic wall at the point of maximum tenderness, absence of changes in the colon wall and absence of color flow on Doppler. CT-Scan findings include an oval lesion with attenuation similar to fat surrounded bu a hyperattenuated ring located near but distinct to the colon, inflammatory changes in the surrounding fat and absence of other abnormalities. The presence of a central hyperdense dot thought to represent a thrombosed vein to the epiploic appendix is a specific sign felt to distinguish epiploic appendagitis from omental torsion. MRI findings of epiploic appendagitis include an oval-shaped lesion, usually one to 4 cm in size, with high signal intensity center and low signal intensity rim on T1-weighted images. Obesity seems a risk factor. If the diagnosis of epiploic appendagitis is made preoperative with certain degree of confidence management can be conservative using pain killers. Most children recover in ten days. If the diagnosis is uncertain then laparoscopy has been found to be effective in diagnosis and management of epiploic appendagitis.