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

• FHI (Fibrous Hamartoma of Infancy)
• Subdermal Fibromatous Tumor of Infancy

What is Fibrous Hamartoma of Infancy? (Definition/Background Information)

• Fibrous Hamartoma of Infancy (FHI or Subdermal Fibromatous Tumor of Infancy) is a highly infrequent tumor seen almost only in infants. This benign tumor appears below the skin (mostly superficial or subdermal) but can grow at subcutaneous locations too
• These soft tissue tumors are generally solitary and are observed in the armpits, groin, or abdominal region. No pain is generally associated with Fibrous Hamartomas of Infancy
• The exact cause of Fibrous Hamartoma of Infancy is unknown, and no specific risk factors have been identified. However, occasionally the tumor is seen in a background of tuberous sclerosis and Williams syndrome (both genetic conditions)
• The healthcare provider may undertake treatment (surgical removal of the tumor) in case it causes worrisome signs and symptoms, else a ‘wait and watch’ approach may be adopted
• The prognosis of Fibrous Hamartoma of Infancy is typically excellent, since these are benign tumors. However, in case of incomplete tumor removal, there is a chance of recurrence

Who gets Fibrous Hamartoma of Infancy? (Age and Sex Distribution)

• Almost all cases of Fibrous Hamartoma of Infancy are described in children below 2 years; 1 in 5 are present at birth (congenital) and over 90% of the tumors are observed before the child reaches the age of 1 year
• The tumor rarely occurs past the age of 10-14 years i.e., after puberty
• Even though the condition affects males and females, boy babies are affected more by FHI (2:1 male-female ratio)
• This tumor is observed worldwide and there is no racial or ethnic group predilection

What are the Risk Factors for Fibrous Hamartoma of Infancy? (Predisposing Factors)

Currently, no risk factors have been identified for Fibrous Hamartoma of Infancy. In rare cases, it is seen in association with the following conditions:

• Williams syndrome: A rare genetic, developmental disorder
• Tuberous sclerosis: A group of genetic disorders affecting multiple organs in the body

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 Fibrous Hamartoma of Infancy? (Etiology)

• The cause of development of Fibrous Hamartoma of Infancy is generally unknown
• In rare cases, cell abnormalities at the genetic level have been observed, but very inconsistently
• Research is currently being undertaken to identify the relevant causal factors

What are the Signs and Symptoms of Fibrous Hamartoma of Infancy?

The signs and symptoms of Fibrous Hamartoma of Infancy may include:

• The presence of a soft mass just below the skin surface (superficial presentation) that is poorly defined/circumscribed. The mass may freely move around when touched or felt
• It is a slow-growing or rapidly-growing tumor that is usually found to be solitary
• The tumor size is about 3-5 cm, though some may grow to large sizes. Generally, there is an absence of pain from the tumor
• The skin on the tumor surface can be involved and show changes; there may be excessive hair growth on the skin
• FHI is mostly seen in the armpits, groin or lower abdominal region, the upper arms, chest and back, and also in the genital region
• In some rare cases, the head, hands and feet may be involved

How is Fibrous Hamartoma of Infancy Diagnosed?

There are a variety of tests the healthcare provider may employ to detect and diagnose Fibrous Hamartoma of Infancy. These may include:

• Physical examination and complete medical history screening
• Imaging studies that may include X-rays, MRI or CT scans of the affected region
• Tumor biopsy of the tumor specimen: A tissue biopsy 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

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 Fibrous Hamartoma of Infancy?

There are no significant complications associated with Fibrous Hamartoma of Infancy. However, in some cases the following may be observed:

• Emotional stress in the parents, since the tumor may cause a concern for cancer
• Recurrence following surgery is seen in 15% of the cases; hence, sometimes more than one surgery may be required to remove the tumor
• Complications from any underlying disorders or conditions, if any present

How is Fibrous Hamartoma of Infancy Treated?

The treatment of Fibrous Hamartoma of Infancy may involve the following:

• For smaller-sized tumors, their surgical removal may not be necessary, unless bothersome signs and symptoms are present. In such cases, the healthcare provider may recommend a ‘wait and watch’ approach and regular checkups
• The treatment of choice is local excisional surgery, which can result in a cure. This is generally the preferred option to treat FHI
• Treatment of underlying genetic disorders, such as Williams syndrome or tuberous sclerosis, if present
• Follow-up care with regular screening and check-ups are important and encouraged

How can Fibrous Hamartoma of Infancy be Prevented?

Currently, there are no known methods to prevent the development of Fibrous Hamartoma of Infancy.

What is the Prognosis of Fibrous Hamartoma of Infancy? (Outcomes/Resolutions)

• The prognosis for Fibrous Hamartoma of Infancy is generally excellent with appropriate treatment, since it is a benign tumor
• There is a risk of tumor recurrence on its incomplete removal, and so, multiple surgeries may be needed in some cases
• In case of an associated genetic disorder, the overall prognosis may be dictated by the severity of the associated disorder (Williams syndrome or tuberous sclerosis)

Additional and Relevant Useful Information for Fibrous Hamartoma of Infancy:

• Williams syndrome is a genetic disorder caused by the deletion of few gene copies on chromosome 7, which involves the elastin gene. The disorder affects multiple organ systems

The following link may help you understand Williams syndrome:

https://www.dovemed.com/diseases-conditions/williams-syndrome/