Introduction
In a small child, the daily bath is always given by the parent. It is thus common for the parent to notice a mass in the abdomen while scrubbing or drying the child. The child may have no symptoms and is unaware of the mass. There may be no pain, redness, discomfort, nor any history of accidental trauma. There may not be any vomiting, abdominal distension, or any major illness in the recent past. The mass is the only sign of something not normal in this child and this being so the common tendency is to ignore the mass hoping it will go away by itself, or take some medicine from the local doctor and forget about the mass. However, this is a very wrong and dangerous approach to take and can be crucial to the ultimate result in that child.
Lump in Abdomen - Causes
There are many reasons for a lump in the abdomen in a child even as young as a few months old to a child who is a few years old. The commonest cause for a lump may be a tumor that may or may not be malignant. Yes, the notion that cancers can only occur in old persons is wrong and cancers of various organs in children are a distinct possibility - known as embryonal cancers and are present in a small size since before birth. These cancers continue to grow after birth and the later they are noticed or investigated for - the larger and more difficult it is to treat them. Not all lumps are cancerous, some are benign lumps and may grow slowly till they are treated. Besides solid organs like the kidneys, liver, adrenal glands, even the intestinal tract may be affected by solid or cystic masses. The effect of the lump may depend on where they are situated, how fast they grow, and can cause pain, obstruction of the intestinal tract, the urinary tract, and so on. The mass can cause external pressure on any tubular organ like the intestine, the ureter, the bile duct, and block it causing a build-up of pressure proximal to the site of obstruction. Cancer of organs can spread locally and engulf important large blood vessels, grow into the wall of the vessel, intestine, or tubular structure. The tumor can also spread through the bloodstream to other organs in the abdomen or outside the abdomen - these are called metastasis. The reason for writing these details is to emphasize the importance of early diagnosis, thorough investigations, ideal therapy that may include surgery, chemotherapy (anti-cancer drugs), and radiation therapy. With proper care and a prolonged follow-up, it is possible to give good results. However, delay in diagnosis and therapy can increase both the mortality and the morbidity due to the mass.
The common point in all is not to wait once a lump is felt in the abdomen. The child must be shown to a good doctor at the earliest so that investigations and diagnosis is made early and therapy can begin soon after that.
Wilm's Tumor
This is a cancer of the kidney and this is an embryonal tumor. This arises from the upper or lower pole of the kidney. It may occur on one side or rarely on both sides simultaneously. Growth is continuous and hence the earlier the detection and therapy, the better is the prognosis for the child. This may be felt as early as a few months of age or even at 2 - 3 years. Before any treatment, the function and presence of the opposite kidney must be confirmed. Also, look for the beginning of a tumor in the opposite kidney. The overall kidney function is checked by blood tests and then surgery is planned. A CT Scan will show better the dimensions of the tumor, the local spread, the state of the vessels, and surgery is planned in that manner. If detected early and well defined, the ideal surgery is to remove the tumor along with the rest of the kidney on that side. This is followed by a microscopic examination of the type of tumor and then the Chemotherapy is begun to remove micro tumor emboli that may already be in the bloodstream. At times in more advanced tumors, radiation therapy may also be added for better results. If the tumor has already spread before the diagnosis, then removal of the kidney may not be possible and the tumor may have extended into the blood vessels. In such a case, the diagnosis may be confirmed by a needle biopsy and the chemotherapy is given in cycles to reduce the mass size, and later go in for surgery to remove the tumor if possible. There are many factors that may play a role in the ultimate prognosis like the size of the tumor, the extent of local spread, the age at diagnosis, the presence of other symptoms like passing blood in urine, etc.
Neuroblastoma
This is another type of cancer in children that arises from the adrenal gland situated just above the kidney. This is also an embryonic tumor and can spread fast to adjacent areas, as well as thru the blood to the liver and the bone. Overall, this tumor has a much poorer prognosis than the Wilms tumor. This too may have few symptoms other than a palpable mass in the abdomen. Once detected by a CT Scan the spread locally and to distant areas is looked for and the intervention is planned. If possible, this tumor is removed in one piece, followed by chemotherapy in cycles. If the tumor is too large to be removed or has spread too much when diagnosed, then Chemotherapy is given first, and then an attempt to remove the tumor surgically is done.
Hepatic Tumor
Tumors of the liver can be of various types some of them are present from before birth, some come up later. The tumors may be malignant or benign. The common ones present at birth are made up of excessive proliferation of the blood vessels and may either bleed within the liver or may cause heart failure and require early surgery to remove the tumor to stop these complications. Here again, an Ultrasound and then a CT scan must be done to get a proper understanding of the extent of the tumor and for planning the surgery. These are benign tumors and hence no further therapy is required except follow up. The malignant tumor may come up later when the child is 4 years or more and these can grow fast, spread both locally and through the bloodstream to distant places in the body, and require thorough investigations and followed by surgical excision. In the operation, a part or entire lobe of the liver needs to be removed. This is later followed by the use of Chemotherapy and if necessary Radiotherapy to get the best result.
Hydronephrosis
This is an accumulation of urine in the pelvis of the kidney due to an obstruction to the passage of urine from the pelvis to the bladder. The stretching and dilatation of the renal pelvis can form a palpable mass in the abdomen. This will be discussed separately later, but requires a proper investigation and then appropriate surgery to relieve the obstruction and allow urine to flow smoothly into the bladder.
Mesenteric Cyst
This is a cyst in the mesentery of the intestines and maybe small or at times a huge double cyst. All of these may present as a mass in the abdomen, with pain due to stretching of the peritoneal covering, or intestinal obstruction due to pressure from outside resulting in abdominal distension, vomiting, inability to eat. An Ultrasound and a CT Scan will delineate the exact size and position of the cyst and the surgery is planned. During the surgery, the cyst may be arising in the mesentery, and if the blood supply to the cyst and the segment of intestine is common, then there is no choice but to remove the cyst along with a segment of the intestine and rejoin the remaining intestine to each other for continuity. These are nonmalignant cysts and no further therapy is required.
Choledochal Cyst
This is again a benign cyst of the tube leading the bile from the liver to the intestine called the bile duct. A large cyst in the bile duct causes obstruction to the flow of bile and can lead to a lump in the abdomen, jaundice due to obstructed bile flow, and pain. This may present at a young age and after investigations kept for surgical excision and joining the remaining duct to the intestine to continue the flow of bile into the intestinal tract as normal.
Lymphoma
This is a malignant condition and is usually noticed as a lump in the abdomen at around 10 years of age. The child may complain of pain in the abdomen, mass palpable, intestinal obstruction. There is an enlarged mass of lymph nodes within the abdomen that have this malignant tumor and more than that there may be an extension of the mass into the adjacent intestine and removing the entire mass may not always be possible. Here, as much of the tumor is removed, sent for microscopic examination, and after confirming the diagnosis, chemotherapy, and radiotherapy needs to be given in cycles. There are 2 types of Lymphomas, of which one variety has a very poor prognosis despite therapy including chemotherapy and radiotherapy.
Invetigations
One of the first investigations asked for in any child with a palpable mass in the abdomen is ultrasonography. This is a simple, easily available noninvasive investigation that helps in many ways. First, it tells us whether the lump is solid or cystic (full of fluid). A solid mass is likely to be a tumor, a cystic mass may be a cyst or collection of urine-hydronephrosis, etc. The second important information given is the organ of origin - i.e where is the mass arising from the kidney, the liver, the adrenal, the intestine, etc. Besides this, other vital information given is the dimensions of the mass the length, width, and thickness; local spread of the tumor if solid, invasion of vital blood vessels in the abdomen, and the presence of another tumor elsewhere in the abdomen that may not be palpable. Also, the other solid organs in the abdomen can also be visualized.
Figure 1: Cystic kidney
Further investigations can be based on this preliminary investigation and will be specific for that organ or system. The investigations may be radiological or blood tests. The blood tests look at the function of the organ from which the tumor is arising; the radiological investigations like CT Scan are required to give more details of the mass to plan the type and timing of surgery and whether chemotherapy is to be given before the surgery. A joint consultation with a good medical oncologist and pediatrician to plan the entire approach makes a difference in the well being of the child and planning the line of therapy and its timing.
Figure2: Solid tumor arising from kidney
Follow up for multiple cycles of chemotherapy is a must for long-lasting results with the surgeon and oncologist to look for spread, recurrence. If there is a problem then a second surgery may be required. Complications in such cases may be inadequate removal of the mass, postoperative bleeding, injury to adjacent non affected vital structures like vessels, other organs, or tubular structures like the intestines or the ureter, etc. Recurrence of the tumor, local, and systemic spread of the tumor to places like lung, liver, brain, bone marrow are also possible.