KASABACH-MERRITT PHENOMENON

TYPES

KASABACH-MERRITT PHENOMENON (KMP) is primarily associated with two specific types of vascular tumors: kaposiform hemangioendothelioma (KHE) and tufted angioma (TA).

1. Kaposiform Hemangioendothelioma (KHE): KHE is a rare, locally aggressive vascular tumor that primarily affects infants and young children. It typically presents as a red or bluish mass under the skin, but it can also occur in internal organs such as the liver or spleen. KHE is characterized by rapidly growing blood vessels and the formation of blood clots within the tumor, leading to low platelet counts and potential bleeding complications.
2. Tufted Angioma (TA): TA is another rare vascular tumor that primarily affects children, although it can also occur in adults. It appears as a reddish or purplish lesion on the skin and can grow slowly over time. Like KHE, TA is characterized by abnormal blood vessel growth and the formation of blood clots within the tumor, resulting in low platelet counts and potential bleeding problems.

Both KHE and TA are considered part of the spectrum of vascular anomalies, and their association with KMP makes them particularly challenging to manage. Prompt diagnosis and appropriate treatment are crucial to prevent complications and ensure the best possible outcomes for individuals affected by these conditions.

SYMPTOMS

KASABACH-MERRITT PHENOMENON (KMP) is characterized by the formation of abnormal blood vessels and severe blood clotting. The symptoms of KMP can vary depending on the location and size of the associated hemangiomas (abnormal blood vessel growths). Here are some common symptoms that may be observed:

1. Visible Mass or Swelling: Hemangiomas associated with KMP can appear as a visible mass or swelling on the skin or in deeper tissues, such as the liver or spleen. These growths may be red, bluish, or purplish in color.
2. Bruising: Individuals with KMP may experience easy bruising or the development of bruises without any apparent trauma. This can be due to the abnormal blood vessels and associated clotting disorder.
3. Bleeding: KMP can lead to bleeding problems due to the formation of blood clots within the hemangiomas. This can cause symptoms such as nosebleeds, gastrointestinal bleeding (resulting in blood in the stool), or excessive bleeding from minor cuts or injuries.
4. Anemia: The presence of large hemangiomas and associated bleeding can lead to a decrease in red blood cell count, resulting in anemia. Symptoms of anemia can include fatigue, weakness, and pale skin color.
5. Organ Dysfunction: In cases where hemangiomas affect internal organs, such as the liver, there may be associated organ dysfunction. This can manifest as abdominal pain, jaundice (yellowing of the skin and eyes), or signs of liver enlargement.

DIAGNOSIS

The diagnosis of KASABACH-MERRITT PHENOMENON (KMP) involves a combination of clinical evaluation, imaging studies, and laboratory tests. Here are the key steps involved in diagnosing KMP:

1. Medical History and Physical Examination: The healthcare provider will start by taking a detailed medical history and conducting a thorough physical examination. They will inquire about symptoms, including the presence of abnormal growths, bleeding tendencies, or organ dysfunction. The physical examination will focus on assessing the location, size, and characteristics of the hemangiomas.
2. Imaging Studies: Imaging techniques such as ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT) scans may be used to evaluate the size, location, and extent of the hemangiomas. These imaging studies can help determine if there are any internal organ involvement and aid in treatment planning.
3. Laboratory Tests: Blood tests are essential to assess the blood clotting profile, including platelet count, coagulation factors, and fibrinogen levels. Decreased platelet counts and abnormal clotting parameters are typically seen in KMP. Additionally, blood tests may be performed to assess liver function and rule out other potential causes of similar symptoms.
4. Biopsy: In some cases, a biopsy of the hemangioma or affected tissue may be necessary to confirm the diagnosis. A small sample is taken for examination under a microscope to determine the specific type of tumor present and rule out other conditions.

TREATMENT

The treatment approach for KASABACH-MERRITT PHENOMENON (KMP) depends on several factors, including the size and location of the hemangiomas, associated symptoms, and individual patient characteristics. Here are some common treatment options that may be considered:

Pharmacotherapy

Medications can be prescribed to help manage the symptoms associated with KMP. Corticosteroids, such as prednisone, may be used to reduce inflammation and suppress the abnormal blood vessel growth. Other medications, such as propranolol or vincristine, may be considered to target the blood vessel abnormalities and inhibit further growth.

Interventional Radiology Procedures

In cases where the hemangiomas are accessible, interventional radiology techniques may be employed. These procedures can involve embolization, which is the injection of substances to block the blood supply to the abnormal blood vessels, or sclerotherapy, which involves injecting a sclerosing agent to shrink the vessels.

Surgical Intervention

Surgical removal of the hemangiomas may be necessary in certain cases. This approach is typically reserved for large, accessible growths that are causing significant symptoms or impairing organ function. Surgery may be combined with other treatment modalities for optimal outcomes.

Supportive Care

Depending on the severity of the symptoms, supportive care measures may be employed. This can include blood transfusions to address anemia or platelet transfusions to manage bleeding tendencies. Close monitoring of blood counts and clotting parameters is crucial to ensure prompt intervention if complications arise.

Multidisciplinary Management

Given the complexity of KMP, a multidisciplinary approach involving specialists from various fields, such as pediatric hematology/oncology, dermatology, interventional radiology, and surgery, is often necessary. This ensures comprehensive evaluation, individualized treatment planning, and ongoing monitoring of the condition.