What are the other Names for this Condition? (Also known as/Synonyms)

• Inflammatory Fibrosarcoma of Spleen
• Plasma Cell Granuloma of Spleen
• Splenic Inflammatory Pseudotumor

What is Inflammatory Myofibroblastic Tumor of Spleen? (Definition/Background Information)

• Inflammatory Myofibroblastic Tumor of Spleen is a very rare, mostly benign tumor of the spleen. They can grow to large sizes and generally occur in younger populations, especially in children
• Inflammatory myofibroblastic tumor (IMT) is generally considered as a benign tumor with aggressive behavior (low-grade tumor), which can occur anywhere in the body
• The cause of Splenic Inflammatory Myofibroblastic Tumor is generally unknown. There are also no well-established risk factors for this tumor type
• The signs and symptoms are generally non-specific, but may include fever, abdominal pain, and weight loss. Complications, such as enlarged spleen and  tumor recurrence on its partial removal, is known to occur
• The mainstay of treatment is a surgical excision (splenectomy) that can be curative. Some tumors are known to shrink and disappear with time
• The prognosis of Inflammatory Myofibroblastic Tumor of Spleen is generally good on complete tumor removal, but some tumors are known to recur and even metastasize (in very rare cases)

Who gets Inflammatory Myofibroblastic Tumor of Spleen? (Age and Sex Distribution)

• Inflammatory Myofibroblastic Tumor of Spleen is typically seen in young adults and children, including in infants. However, older adults are also affected
• Very few cases of IMT of Spleen have been recorded in the medical literature (less than 100 cases reported worldwide)
• Both males and females are affected and no gender preference is seen
• All races and ethnic groups are at risk for the condition

Note: Most inflammatory myofibroblastic tumors are found in the lung, which is the most common site of the tumor. In such cases, these tumors are frequently diagnosed in middle-aged adults. However, in contrast, the average age of presentation for extrapulmonary IMT (IMT outside the lung) is around 10 years.

What are the Risk Factors for Inflammatory Myofibroblastic Tumor of Spleen? (Predisposing Factors)

• Presently, the specific risk factors for Splenic Inflammatory Myofibroblastic Tumor are unknown or unidentified

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Inflammatory Myofibroblastic Tumor of Spleen? (Etiology)

The cause of development of Inflammatory Myofibroblastic Tumor of Spleen is generally unknown.

• Some research scientists believe that the cause of the condition is mostly due to genetic mutations, which results in tumor formation. In over 40% of the tumors, ALK gene mutation has been observed
• Some believe that the inflammatory myofibroblastic tumor is the result of an inflammatory reactive process and not a true tumor
• It is also believed by some researchers that the tumor may arise due to viral infections caused by human herpes virus 8 (HHV8) or Epstein-Barr virus (EBV). EBV is thought to play an important role in the development of IMT of Spleen, in some cases

What are the Sign and Symptoms of Inflammatory Myofibroblastic Tumor of Spleen?

The signs and symptoms depend on the size of the tumor. The signs and symptoms of Inflammatory Myofibroblastic Tumor of Spleen can be non-specific and may include:

• Small tumors usually do not cause any symptoms. But, occasionally they may become painful, if they compress surrounding structure
• Presence of mass in the abdomen upon abdominal examination
• Abdominal pain, which can be due to tumor growth
• Fever and fatigue
• Weight loss
• Anemia

The tumor may range in size from 5-11 cm. The Inflammatory Myofibroblastic Tumor of Spleen is typically well-defined and non-homogenous in appearance.

How is Inflammatory Myofibroblastic Tumor of Spleen Diagnosed?

A diagnosis of Inflammatory Myofibroblastic Tumor of Spleen may be undertaken using the following tests and exams:

• Complete evaluation of family (medical) history, along with a thorough physical examination
• Liver function tests
• Plain X-ray of the abdomen
• Ultrasound scan of the abdomen
• CT or CAT scan with contrast of the abdomen usually shows a well-defined mass. This radiological procedure creates detailed 3-dimensional images of structures inside the body
• MRI scans of the abdomen: Magnetic resonance imaging (MRI) uses a magnetic field to create high-quality pictures of certain parts of the body, such as tissues, muscles, nerves, and bones. These high-quality pictures may reveal the presence of the tumor

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include: 

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Core biopsy of the spleen
• Open biopsy of the spleen

Invasive diagnostic procedures such as:

• Laparoscopy: A special device is inserted through a small hole into the abdomen, to visually examine it. If necessary, a tissue sample is obtained for further analysis. Exploration of the abdomen using a laparoscope is called ‘exploratory laparoscopy’
• Laparotomy: The abdomen is opened through an incision for examination, and if required, a biopsy sample obtained. Exploration of the abdomen using laparotomy procedure is called ‘exploratory laparotomy’

Tissue biopsy of the tumor:

• A tissue biopsy of the nodule is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Note: Inflammatory Myofibroblastic Tumors are very rare. Due to this, it typically causes diagnostic challenges to the pathologist while trying to establish an accurate diagnosis.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Inflammatory Myofibroblastic Tumor of Spleen?

Some potential complications of Inflammatory Myofibroblastic Tumor of Spleen include:

• They can mimic splenic cancer and cause considerable emotional stress in the affected individual
• Swollen spleen (splenomegaly)
• If the spleen gets too large, it may rupture (termed as a splenic rupture)
• Spleen dysfunction due to large tumors
• Recurrence of the tumor after treatment, especially due to partial removal of IMT; however, recurrences are generally rare with this tumor type
• In rare cases, these tumors can be locally aggressive
• Also, very rarely, these tumors are known to metastasize; in which case the tumor is known as Malignant Inflammatory Myofibroblastic Tumor

How is Inflammatory Myofibroblastic Tumor of Spleen Treated?

Inflammatory Myofibroblastic Tumor of Spleen may be treated through the following measures:

• Surgical removal of the entire tumor is the preferred method of treatment. Usually a partial or complete splenectomy is undertaken
• In young children, if the tumors cannot be surgically removed, then corticosteroid administration is found to be beneficial
• Occasionally, the tumor is noted to regress on its own with the administration of antibiotics and NSAIDs
• Chemotherapy may help, if the condition recurs , if there is a local invasion, or a distant metastasis is noted (in very rare cases)

Observation and periodic checkups to monitor the condition is recommended following treatment.

How can Inflammatory Myofibroblastic Tumor of Spleen be Prevented?

Presently, there are no specific methods or guidelines to prevent Inflammatory Myofibroblastic Tumor of Spleen.

What is the Prognosis of Inflammatory Myofibroblastic Tumor of Spleen? (Outcomes/Resolutions)

• An early diagnosis and prompt treatment of Inflammatory Myofibroblastic Tumor of Spleen generally yields better outcomes than a late diagnosis and delayed treatment
• The prognosis on timely surgical removal of the tumor is generally good. On a complete excision and removal, Splenic IMT is generally not known to recur
• Some tumors are known to spontaneously regress and disappear. But, some tumors are known to grow aggressively, recur, or even metastasize (occasionally)

Additional and Relevant Useful Information for Inflammatory Myofibroblastic Tumor of Spleen:

The following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/