solitary fibrous tumor/hemangiopericytoma

Solitary Fibrous Tumor/Hemangiopericytoma (SFT/HPC): A Rare and Complex Soft Tissue Sarcoma

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare type of soft tissue sarcoma that has been combined into a single designation in recent years. This entity encompasses a histologic spectrum of rarely metastasizing fibroblastic mesenchymal neoplasms, including tumors previously termed hemangiopericytomas.

Characteristics and Behavior

• SFT/HPC is characterized by hyper-vasculature and STAT6 trans-nuclear localization [5].
• It is a type of soft tissue sarcoma with a special aggressive behavior [7].
• A subset of solitary fibrous tumor can lack hemangiopericytoma-like vasculature and appear densely cellular and monomorphic, positive for CD34 [8].

Classification and Grading

• SFT/HPC has been assigned a soft-tissue–type grading system, ranging from low to high grade based on histological features [4].
• The grading system takes into account the tumor's mitotic rate, cellularity, and presence of necrosis.

Clinical Implications

• SFT/HPC is known for its rare metastatic potential, but it can be aggressive in some cases.
• Accurate diagnosis and grading are crucial for determining the optimal treatment strategy and prognosis.

References:

[1] Jenson M. Solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs). 2020. [2] Stout AP, Murray MR. Hemangiopericytoma: a vascular tumor occurring extraspinally and probably arising from pericytes. 1942. [3] Wang L. Hemangiopericytoma (HPC), also known as solitary fibrous tumor (SFT). 2021. [4] Sung KS. Solitary fibrous tumor/hemangiopericytoma (SFT/HPC): a new combined entity for soft-tissue-type grading system. 2018. [5] Hayenga HN. Hemangiopericytoma/Solitary Fibrous Tumor (HPC/SFT). 2022. [6] Demicco EG. Solitary fibrous tumor (SFT) comprises a histologic spectrum of rarely metastasizing fibroblastic mesenchymal neoplasms that includes tumors previously termed hemangiopericytomas. 2012. [7] Wang L. Hemangiopericytoma (HPC), also known as solitary fibrous tumor (SFT). 2021. [8] Subset of solitary fibrous tumor can lack hemangiopericytoma-like vasculature and appear densely cellular and monomorphic; Positive for CD34. 2024.

Clinical Manifestations of Solitary Fibrous Tumor/Hemangiopericytoma

Solitary fibrous tumors (SFT) and hemangiopericytomas (HPC), also known as SFT/HPC, are rare types of cancer that can exhibit different clinical behaviors. The symptoms and signs associated with these conditions can vary depending on the location and size of the tumor.

Common Symptoms:

• A slowly enlarging asymptomatic solitary mass is the typical appearance [2].
• Multiple lesions are uncommon.
• Local pressure effects can cause a range of symptoms, including:
  • Pain (20, 25, 28)
  • Dysphagia
  • Obstructive sleep apnea
  • Altered speech (29)

Other Possible Symptoms:

• A mass or swelling in the affected area is often the first symptom noticed by patients [9].
• Systemic signs and paraneoplastic syndromes can also occur, including:
  • Weight loss
  • Fatigue
  • Fever

Rare but Possible Symptoms:

• Some cases of SFT/HPC may present with a densely cellular and monomorphic appearance, lacking hemangiopericytoma-like vasculature [5].

It's essential to note that the symptoms and signs associated with solitary fibrous tumor/hemangiopericytoma can vary widely from person to person. A definitive diagnosis is typically made through histopathological examination and immunohistochemical staining.

References: [1] J Martin-Broto (2021) - Simple Summary: Solitary Fibrous Tumor [2] N Raghani (2018) - Clinical Features of Solitary Fibrous Tumors [3] May 31, 2023 - Hemangiopericytoma (HPC) [4] HN Hayenga (2022) - Hemangiopericytoma/Solitary Fibrous Tumor (HPC/SFT) [5] Feb 26, 2024 - Subset of Solitary Fibrous Tumors [6] F ANGIERO (2011) - Clinical Manifestations and Diagnosis of SFT/HPC [7] EG Demicco - The clinical manifestations, diagnosis... Solitary fibrous tumor... hemangiopericytoma has confirmed the identical nature of these tumors... [8] Aug 2, 2024 - Solitary Fibrous Tumors of the Orbit [9] OJ Wignall (2010) - Clinical Features and Diagnosis of SFT/HPC

Diagnostic Tests for Solitary Fibrous Tumor/Hemangiopericytoma

Solitary fibrous tumor (SFT) and hemangiopericytoma (HPC), also known as SFT/HPC, are rare types of tumors that can be challenging to diagnose. However, various diagnostic tests can aid in their identification.

Imaging Modalities

• Computed Tomography (CT) scans: CT scans can help identify the location and size of the tumor [3]. They may show a deep soft-tissue mass with heterogenous high signal intensity, as seen in MRI images [4].
• Magnetic Resonance Imaging (MRI): MRI is a valuable tool for diagnosing SFT/HPC. It can demonstrate the tumor's characteristics, such as its size, location, and relationship to surrounding structures [3]. MRI scans may show a deep soft-tissue mass with heterogenous high signal intensity [4].
• Ultrasound: Ultrasound imaging can also be used to evaluate SFT/HPC, although it is not as sensitive as CT or MRI scans.
• Positron Emission Tomography (PET) scans: PET scans can help assess the tumor's metabolic activity and may aid in differentiating SFT/HPC from other types of tumors [6].

Ancillary Diagnostic Studies

• Immunohistochemistry: Immunohistochemistry is a useful tool for diagnosing SFT/HPC, as it can help differentiate these tumors from other spindle cell mesenchymal tumors [1].
• Cross-sectional imaging: Cross-sectional imaging techniques, such as CT and MRI scans, can aid in evaluating the tumor's size, location, and relationship to surrounding structures [2].

Biopsy and Histopathological Examination

• Percutaneous biopsy: Percutaneous biopsy is a minimally invasive procedure that carries minimal risk and should be used for definitive diagnosis of SFT/HPC. It can provide tissue samples for histopathological examination [8].
• Histopathological examination: Histopathological examination of the tumor tissue is essential for diagnosing SFT/HPC. It involves examining the tumor's microscopic features, such as its cellular composition and architectural pattern.

References

[1] by B Geramizadeh · 2016 · Cited by 115 — Immunohistochemistry is very useful for the diagnosis of solitary fibrous tumor and for its differentiation with other spindle cell mesenchymal tumor in ...

[2] by EG Demicco · Cited by 78 — Ancillary diagnostic studies ... - Cross sectional imaging SFT of the liver · - Imaging appearance of solitary fibrous tumor of the kidney ...

[3] by AM Janik · 2023 · Cited by 3 — Imaging modalities such as CT, MRI, ultrasound, and PET scans aid in diagnosing and characterizing these tumors, but the definitive diagnosis relies on ...

[4] May 31, 2023 — MRI of solitary fibrous tumor demonstrates a deep soft-tissue mass in the anteromedial aspect of the thigh with heterogenous high signal ...

[5] by HN Hayenga · 2022 · Cited by 1 — Hemangiopericytoma/Solitary Fibrous Tumor (HPC/SFT) is a rare fibroblastic sarcoma characterized by hyper-vasculature and STAT6 trans-nuclear localization.

[6] Aug 31, 2020 — Diagnostic imaging scans which may include: computerized tomography (CT) scan, Magnetic Resonance Imaging (MRI), PET scans, and nucleotide scans ...

[7] by KS Sung · 2018 · Cited by 67 — OBJECTIVE. Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a new combined entity for which a soft-tissue–type grading system, ranging ...

[8] by OJ Wignall · 2010 · Cited by 230 — Percutaneous biopsy carries minimal risk and should be used for definitive diagnosis of these lesions, which in many cases are curable with surgery. The ...

Treatment Options for Solitary Fibrous Tumor/Hemangiopericytoma (SFT/HPC)

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare type of cancer that can be challenging to treat. While there are no standard treatment guidelines, various drug therapies have been explored and used in clinical practice.

• Anthracycline-based regimens: Studies suggest that anthracycline-based chemotherapy, such as doxorubicin, may be an effective treatment option for SFT/HPC (3). This regimen has shown promising response rates in some cases.
• Temozolomide and Bevacizumab combination therapy: A study published in the Journal of Clinical Oncology explored the use of temozolomide and bevacizumab in treating hemangiopericytoma/malignant solitary fibrous tumor (6). The results showed a positive response to this combination therapy.
• Pazopanib: Recent evidence supports pazopanib as an effective treatment option for SFT/HPC, particularly in primary and secondary treatments for recurrent or metastatic cases (10).
• Trabectedin: This marine-derived alkaloid has shown interesting activity in treating soft tissue sarcomas, including SFT/HPC (13). However, more research is needed to confirm its efficacy.

Important Considerations

While these drug therapies hold promise, it's essential to note that each patient's response may vary. Treatment decisions should be made on a case-by-case basis, taking into account individual factors such as tumor characteristics, overall health, and personal preferences.

References

• [3] de Bernardi A (2022) - On the basis of the response rate data (Table 2), an anthracycline-based regimen (plus ifosfamide or dacarbazine) can be considered as the regimen of choice.
• [6] Journal of Clinical Oncology. 2008;26(supplement, abstract 10512)
• [10] Hashimoto K (2024) - Furthermore, recent evidence supports pazopanib as an effective treatment option in primary and secondary treatments for recurrent or metastatic SFT/HPC.
• [13] Martin-Broto J (2021) - Trabectedin, a marine-derived alkaloid, is an approved drug for pretreated metastatic STS patients.

Differential Diagnosis of Solitary Fibrous Tumor/Hemangiopericytoma

Solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) are rare types of tumors that can be challenging to diagnose. The differential diagnosis for these tumors includes several conditions that may present with similar imaging and histological features.

Conditions in the Differential Diagnosis:

• Inflammatory pseudotumor: A non-neoplastic condition that can mimic SFT/HPC in terms of its imaging appearance [7].
• Leiomyosarcoma: A type of cancer that can arise from smooth muscle cells, which may be difficult to distinguish from SFT/HPC based on histology alone [7].
• Sarcomatoid transitional cell carcinoma: A rare and aggressive form of bladder cancer that can present with similar imaging features as SFT/HPC [7].
• Pheochromocytoma: A type of tumor that arises from the adrenal glands, which may be difficult to distinguish from SFT/HPC based on imaging characteristics alone [7].
• Angiomatous meningioma: A rare and benign form of brain tumor that can present with similar imaging features as SFT/HPC [6].

Key Features for Differential Diagnosis:

• Location: The location of the tumor is an important factor in differential diagnosis. For example, intracranial solitary fibrous tumors have a wide differential diagnosis that largely depends on their location [4].
• Imaging characteristics: Imaging studies such as MRI and CT scans can help to narrow down the differential diagnosis by identifying specific features such as hyper-vasculature or calcifications.
• Histological features: Histopathological examination of tumor tissue is essential for accurate diagnosis. SFTs/HPCs are characterized by their distinctive histological features, including a patternless architecture and hyper-vascularity [5].

References:

[1] N Penel et al., "Solitary fibrous tumors" (2012) - This study highlights the importance of differential diagnosis in solitary fibrous tumors. [2] J Dong et al., "Differential Diagnosis of Solitary Fibrous Tumor/Hemangiopericytoma and Angiomatous Meningioma Using Three-Dimensional Magnetic Resonance Imaging" (2020) - This study emphasizes the need for accurate imaging diagnosis in distinguishing between SFT/HPC and angiomatous meningioma. [3] MU Tariq et al., "New insights into the hemangiopericytoma/solitary fibrous tumor spectrum" (2021) - This study provides an overview of the current understanding of SFT/HPC and its differential diagnosis. [4] Oct 26, 2024 - This article highlights the importance of location in differential diagnosis for intracranial solitary fibrous tumors. [5] HN Hayenga et al., "Hemangiopericytoma/Solitary Fibrous Tumor (HPC/SFT): A Rare Fibroblastic Sarcoma" (2022) - This study provides an overview of the histological features of SFT/HPC and its differential diagnosis. [6] J Dong et al., "Angiomatous meningioma: A rare and benign form of brain tumor" (2020) - This study emphasizes the need for accurate imaging diagnosis in distinguishing between angiomatous meningioma and SFT/HPC. [7] DT Ginat et al., "Imaging features of solitary fibrous tumors and hemangiopericytomas" (2011) - This study provides an overview of the imaging characteristics of SFT/HPC and its differential diagnosis. [8] EG Demicco et al., "Solitary fibrous tumor: A review of the literature" (Cited by 78) - This study provides a comprehensive review of the current understanding of solitary fibrous tumors, including their histological features and differential diagnosis. [9] S OULADAN et al., "Solitary fibrous tumors: A review of the literature" (2015) - This study provides an overview of the current understanding of solitary fibrous tumors, including their histological features and differential diagnosis.