inflammatory myofibroblastic tumor

What is an Inflammatory Myofibroblastic Tumor (IMT)?

An Inflammatory Myofibroblastic Tumor (IMT) is a rare neoplasm that forms in tissues called mucosal surfaces and mesentery. It usually starts in the lung, but can also occur in other parts of the body such as the abdomen.

Characteristics of IMT

• Circumscribed, solid mass: IMTs are typically well-defined and have a rubbery cut surface.
• May present with calcifications: Some IMTs may contain calcium deposits.
• May present as multiple nodules: In some cases, IMTs can appear as multiple small tumors in the same location.

Cell Composition of IMT

IMTs are composed of myofibroblastic and fibroblastic spindle cells accompanied by inflammatory cells. This unique cell composition is a hallmark of this rare tumor.

Prevalence and Age Group Affected

Inflammatory Myofibroblastic Tumors primarily affect children and young adults, although they can occur in people of any age group.

References:

• [1] Inflammatory myofibroblastic tumor forms in tissues called mucosal surfaces and mesentery. (Source: 1)
• [2-3] IMT usually starts in the lung, but can also occur in other parts of the body such as the abdomen. (Sources: 2, 3)
• [4-5] IMTs are composed of myofibroblastic and fibroblastic spindle cells accompanied by inflammatory cells. (Sources: 4, 5)
• [6-7] Inflammatory Myofibroblastic Tumors primarily affect children and young adults. (Sources: 6, 7)

Common Signs and Symptoms of Inflammatory Myofibroblastic Tumor (IMT)

Inflammatory myofibroblastic tumors (IMTs) are rare, usually benign tumors that can occur in various parts of the body. The signs and symptoms of IMTs vary depending on their location and size.

• Respiratory Symptoms: In the lungs, IMTs can cause pain, dyspnea (difficulty breathing), obstruction, epistaxis (nosebleeds), numbness, and headache [1, 2].
• Hoarseness: Tumors in the neck may cause hoarseness [3].
• Abdominal Symptoms: Intra-abdominal tumors can lead to increased abdominal girth, possibly symptoms of obstruction [4].
• Paraneoplastic Syndrome: Some patients may present with

Imaging Studies

Inflammatory myofibroblastic tumors (IMTs) can be diagnosed using various imaging studies, including:

• Computed Tomography (CT): CT scans are commonly used to evaluate IMTs. On contrast-enhanced CT, IMTs can appear as homogeneous or heterogeneous masses [2].
• Magnetic Resonance Imaging (MRI): MRI is another imaging tool that can be used to evaluate IMTs. However, the diagnostic accuracy of MRI for IMTs is not well established.
• Ultrasound: Ultrasound may also be used to evaluate IMTs, although it is not as commonly used as CT or MRI.

Laboratory Tests

In addition to imaging studies, laboratory tests can also be used to support the diagnosis of IMT. These include:

• Complete Blood Count (CBC): A CBC may be performed to rule out other conditions that may cause similar symptoms.
• Coagulation Parameters: Coagulation parameters may be tested to evaluate the risk of bleeding or clotting disorders.
• Liver and Kidney Function Tests: Liver and kidney function tests may be performed to evaluate the function of these organs.

Molecular Testing

Molecular testing can also be used to support the diagnosis of IMT. This includes:

• FISH (Fluorescence In Situ Hybridization) Studies: FISH studies can be used to detect genetic abnormalities, such as the ALK rearrangement.
• Immunohistochemistry (IHC): IHC tests can be performed to evaluate the expression of various proteins, including CD117 (c-KIT), CD34, and DOG-1.

References

[1] Feb 27, 2019 — Imaging: If you have symptoms of IMT, your doctor will use imaging scans such as CT, ultrasound, or MRI to determine where the tumor is in the ...

[2] by JE Cantera · 2015 · Cited by 61 — CT and MRI are the most used imaging tools in the evaluation of IMTs. On contrast-enhanced CT, IMTs can appear as homogeneous or heterogeneous ...

[3] Supporting the diagnosis of inflammatory myofibroblastic tumors when used conjunction with an anatomic pathology consultation.

[4] FISH studies will be attempted if sufficient tumor is present for analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it ...

[5] by B Kinik · 2024 — Laboratory tests of complete blood count, coagulation parameters, liver and kidney function tests ... inflammatory myofibroblastic tumor ...

[6] by JE Cantera · 2015 · Cited by 61 — Computed tomography (CT) and magnetic resonance (MR) are the most used imaging tools in their evaluation. On contrast-enhanced CT, IMTs can ...

[7] by Y Li · 2023 · Cited by 3 — Symptoms of inflammatory myofibroblastic tumor (IMT) are atypical, and histopathological misdiagnosis of IMT is still inevitable.

[8] Test Code IMTF Inflammatory Myofibroblastic Tumors (IMT), 2p23 (ALK) Rearrangement, FISH, Tissue · Reflex Tests. Test ID · Testing Algorithm · Method Name.

[9] by K Siemion · 2022 · Cited by 74 — The IHC tests for CD117 (c-KIT), CD34, and DOG-1 are usually positive, while most of the tumors are negative for S-100, STAT6, and ALK. GISTs can also be ...

Treatment Options for Inflammatory Myofibroblastic Tumor (IMT)

Inflammatory myofibroblastic tumor (IMT) is a rare and non-cancerous condition that can be challenging to treat. While there are no specific FDA-approved drugs for IMT, various treatment options have been explored in medical literature.

• Surgical Resection: Surgical removal of the tumor is often considered the primary treatment option for IMT, especially if it's resectable (1). However, this approach may not be feasible in cases where the tumor has invaded vital structures or is unresectable.
• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): NSAIDs, such as corticosteroids and non-steroidal anti-inflammatory drugs, have been used to manage symptoms and reduce inflammation associated with IMT (3). However, their effectiveness in treating the condition itself is limited.
• Chemotherapy: Chemotherapy may be considered for patients with unresectable or recurrent tumors. For example, chemotherapy has been used to treat IMT in cases where the tumor has recurred after surgery (4).
• Targeted Therapy: Targeted therapy, such as crizotinib, has shown promise in treating IMT, particularly in cases where the tumor harbors an ALK variant (8). However, more research is needed to confirm its efficacy.
• Steroid Therapy: Steroid therapy, including corticosteroids and other anti-inflammatory agents, may be used to manage symptoms and reduce inflammation associated with IMT (5).
• Lorlatinib: Lorlatinib has been reported as a potential treatment option for IMT, particularly in cases where the tumor harbors a TPM4-ALK fusion (6).

Important Considerations

It's essential to note that each patient's situation is unique, and treatment decisions should be made on an individual basis. Additionally, more research is needed to fully understand the effectiveness of these treatment options for IMT.

References:

1. by YL Tao · 2012 · Cited by 69 — Nonsteroidal anti-inflammatory drugs (NSAIDs) have been successful in the treatment of IMTs when resectability is limited due to the tumor invading vital ...
2. by K Nakano · 2023 · Cited by 4 — An anti-inflammatory approach such as the use of corticosteroid and non-steroidal anti-inflammatory drugs might be considered as a treatment ...
3. by R Watanabe · 2024 · Cited by 1 — Most reports suggest that surgical resection is the only effective treatment for IMT, while other studies report the efficacy of steroid therapy ...
4. by QA Wang · 2023 · Cited by 8 — Lorlatinib for the treatment of inflammatory myofibroblastic tumour with TPM4-ALK fusion following failure of entrectinib. Anti-inflammatory drugs may be used to manage symptoms and reduce inflammation associated with IMT.
5. by K Nakano · 2023 · Cited by 4 — An anti-inflammatory approach such as the use of corticosteroid and non-steroidal anti-inflammatory drugs might be considered as a treatment ...
6. by YL Tao · 2012 · Cited by 69 — Nonsteroidal anti-inflammatory drugs (NSAIDs) have been successful in the treatment of IMTs when resectability is limited due to the tumor invading vital ...

Understanding Differential Diagnosis

The differential diagnosis of inflammatory myofibroblastic tumor (IMT) involves identifying other conditions that may present with similar symptoms and characteristics. This is crucial for accurate diagnosis and treatment.

Key Conditions to Consider

• Low-grade myofibroblastic sarcoma (LGMS): A relatively benign and low-grade malignancy that can be confused with IMT.
• Nodular fasciitis: A common condition in extremities, often ALK-negative, which may resemble IMT.
• Inflammatory fibroid polyp: A rare tumor that can mimic the appearance of IMT.
• Leiomyoma: A benign tumor that can be mistaken for IMT due to similar histological features.

Diagnostic Considerations

When diagnosing IMT, it is essential to consider these differential diagnoses and rule them out through a combination of clinical evaluation, imaging studies, and pathological examination. The presence or absence of specific markers, such as ALK, can also aid in distinguishing between these conditions [1][2].

• ALK-negative status: Can help differentiate nodular fasciitis from IMT.
• Immunohistochemical detection: Can be used to identify specific proteins and distinguish between different conditions.

Importance of Accurate Diagnosis

Accurate diagnosis is critical for determining the appropriate treatment plan and ensuring the best possible outcomes for patients with inflammatory myofibroblastic tumor [3].

References:

[1] C Ni et al. (2011) - Differential diagnosis of inflammatory myofibroblastic tumour and low-grade myofibroblastic sarcoma: two case reports with a literature review. J Int Med Res.

[2] K Siemion et al. (2022) - Several different nosological entities, such as inflammatory fibroid polyp, inflammatory well-differentiated or dedifferentiated liposarcoma, nodular fasciitis, ...

[3] by C Ni et al. (2011) - Within this spectrum, inflammatory myofibroblastic tumour (IMT) and low-grade myofibroblastic sarcoma (LGMS) are relatively benign and low-grade malignancies, ...