A hemophilic pseudotumor (HP), also called a hemophilic cyst, is characterized by an encapsulated, recurrent chronic muscle hematoma, which may enlarge progressively and end up developing the form of a tumor.¹ It is a well-established yet rare complication affecting between 1 and 2% of individuals with severe hemophilia.² Hemophilia is a rare X-linked congenital bleeding disorder characterized by a deficiency of coagulation factor VIII (FVIII), called hemophilia A, or factor IX (FIX), called hemophilia B.³

Hemophilia is prevalent worldwide and occurs in all racial and socioeconomic groups.⁴ As per the 2023 annual report of the World Hemophilia Federation (WFH), globally there are 218,804 people with hemophilia, with hemophilia A being more common than hemophilia B, occurring in 80%–85% of all hemophilia cases, while hemophilia B occurs in 15%–20% of all hemophilia cases.^3,5 In 2025, the number of visits of hemophilia patients in our center is 82 children. Most patients are identified via referrals or as a direct result of active family screening. However, in most countries in Asia, not all patients are identified for reasons including lack of awareness, paucity of required facilities, rural residence, and late referral.⁶

Hemophilic pseudotumor was first described by Starker in 1918 and is associated with high morbidity and mortality. The clinical manifestations are not well defined and depend on the affected area.⁷ Prevention is essential for avoiding the complications of muscle hematomas (pseudotumor, compartment syndromes, and peripheral nerve lesions) in hemophilic patients. In this case report, we present moderate hemophilia A with a hemophilic pseudotumor. Written informed consent was obtained from the patient’s parents/legal guardians for the publication of this case report and accompanying images.

A 3-year-and-3-month-old boy was referred from a secondary hospital due to a mass on his left maxilla for 3 weeks prior and getting bigger since 1 week prior to hospital admission. There was a previous history of trauma before the mass appeared. The patient started to look pale, and loss of appetite was observed for the last one week. At that time, he was brought to a secondary hospital and suspected of maxillary carcinoma. After undergoing several examinations and blood transfusion, the patient was referred to tertiary hospital to get further examinations and therapy.

On the day of admission, the mass on the left maxilla was around 5 cm, bluish in color, immobile, warm, soft on palpation, and with some crusts on it, suggesting previous bleeding. The second day of admission, the boy accidentally scratches the mass, and then the blood leaks out again. The mass makes it difficult for the patient to open his left eye, but it did not cause any breathing difficulty. There was no previous bleeding history in other regions than the maxillary mass. There was no previous history of fever, headache, joint pain, rash, weakness, palpitation, bloody cough, or vomit. No significant change in body weight for the last 3 months.

The patient experienced an accident 3 months prior to admission. At the end of July 2024, the patient hit his right cheek in the bathroom tub, and then a lump with a diameter of around 1–2 cm appeared. The lump did not show any sign of bleeding; then it started to deflate after 3 days without therapy. At the beginning of August 2024, another lump began to appear on the left cheek (the same location of the current tumor) with a diameter of 1–2 cm. The lump appeared after being hit by the same bathroom tub. The lump was painless and did not cause complaints until 1 week prior to hospital admission; the lump enlarged quickly to around 5 cm, and the color changed from the previously normal skin color to bluish. The child accidentally scratched it, and the bleeding occurred.

Hemophilic pseudotumor (HP) has been shown to occur at different sites, most commonly in the long bones of the lower extremities and pelvis, which are constantly at risk of trauma. This can be attributed to accidental falls while walking.^7,8 In children, there is a predilection for distal pseudotumor, which occurs in the small bones of the hands and feet. They tend to be multiple and have a better prognosis.⁹ However, in rare cases, it may occur in the craniofacial region, specifically involving the maxillary bone,⁷ as seen in the patient described in this case report.

Most HP predominantly occurs in males due to the X-linked recessive inheritance pattern of hemophilia, which means that males, having only one X chromosome, are more susceptible to developing the condition.⁷ A female with one X chromosome affected is called a carrier of hemophilia. A hemophiliac father passes his only X chromosome down to all his daughters, so they will always get his hemophilia allele and be heterozygous (carriers).¹⁰

The clinical manifestations of HP vary depending on the anatomical location and the type of tissue affected.⁷ HP manifests initially as painless, solid masses that adhere to deeper tissues. Though initially asymptomatic, they can later lead to pathological fractures.¹¹ A classification of HP has been proposed based on the affected tissue type: Type I occurs in soft tissue (14.3%), Type II in the subperiosteal region, and Type III within bone (85.7%). In intraosseous lesions, they typically present as cystic, expansive, and asymptomatic structures, but they can cause fractures or dysfunction in the area. When affecting soft tissues, it behaves as an expanding hematoma.⁷

The HP formation typically requires two primary factors: a bleeding disorder (such as hemophilia) and a triggering traumatic event.⁷ A prior history of trauma is elicited in about half of the cases of pseudotumor. Hemophilia should be suspected in individuals with a history of any of these symptoms: easy bleeding, spontaneous bleeding, or excessive bleeding from trauma.³ Late symptoms of mucosal bleeding and delayed cessation of bleeding in children are key indicators of moderate hemophilia. If hemophilia is suspected in a patient, family abnormal bleeding history should be obtained.¹² The presence of a positive family history of bleeding and parental consanguinity, together with bleeding tendencies in early childhood, most likely suggests an inherited bleeding disorder.¹³ According to Quiroz-Gomez et al., most of the pseudotumor patients had hemophilia type A, while two had hemophilia type B. Additionally, one case involved a patient with von Willebrand disease and one case of pseudotumor were reported in a patient without hemophilia.⁷

Screening tests to identify patients with suspected bleeding disorders are platelet count, bleeding time (BT), prothrombin time (PT), and activated partial thromboplastin time (aPTT).^3,13,14 Initial evaluation of a bleeding disorder should begin with obtaining a complete blood count to exclude thrombocytopenia, as well as evaluate for other white blood cell (WBC) or red blood cell (RBC) abnormalities. The peripheral blood smear should be reviewed to determine additional information about WBC abnormalities, such as malignant blasts suggestive of leukemia, and RBC abnormalities, such as schistocytes.¹⁰ The presence of anemia may indicate significant blood loss.¹³ At the previous hospital, the patient’s level of Hb decreased to 7.0 g/dL, indicating bleeding had occurred, without thrombocytopenia.

Factors VIII and IX are known to be central to the process of blood coagulation and for the adequate generation of thrombin.¹⁵ The severity of bleeding in hemophilia is generally correlated with the clotting factor level.³ The aPTT evaluates the intrinsic and common coagulation pathways (factors VIII, IX, XI, XII, V, X, II, and fibrinogen).¹⁴ The clotting factor level ≥ 1 percent of normal and ≤ 5 percent with bleeding on the head region following trauma indicates moderate hemophilia A.^3,16 In this case, the patient had a prolonged intrinsic pathway of bleeding, and the quantitative assay of FVIII was 1%, with the presentation of a hemophilic pseudotumor.

The term “pseudotumor” derives from the roentgenographic skeletal changes consisting of areas of bone destruction and new bone formation as well as calcification and/or ossification of surrounding soft tissues, resembling a malignant skeletal tumor, particularly osteosarcoma.¹⁷ The pseudotumor grows as a chronic, slowly expanding, encapsulated cystic mass as a result of recurrent hemorrhage in extraarticular musculoskeletal systems.¹⁸ A HP is a rare complication occurring in 1–2% of patients with severe cases of hemophilia (clotting factor level, < 1% of normal). Patients with HP present with painless palpable masses or with painful crises due to episodic acute bleeding into the tumor. Most of the morbidity from pseudotumor is due to their compressive effect on surrounding structures, including bone destruction, muscle necrosis, and skin necrosis. Depending on the area involved, the symptoms include palpable masses, numbness, weakness, and neuralgia.¹⁹ According to Quiroz-Gomez et al., in the maxillary region, four cases reported swelling and bleeding as clinical manifestations; others included epistaxis and proptosis.⁷

Diagnosis of hemophilic pseudotumor is based primarily on clinical suspicion and imaging. Plain x-rays and CT prove useful for evaluating bone involvement. Ultrasound is a suitable method for diagnosing tumors of soft tissue. MRI is the imaging of choice for diagnosing pseudotumor, as it is the most sensitive method for characterizing the distinct stages of evolution of the hematoma and enables multiplanar imaging. One limitation of MRI is its inability to allow differentiation between acute and subacute hematomas and abscesses.⁹ The differential diagnosis would include aggressive lesions or processes such as infection, amyloid arthropathy, or Ewing’s sarcoma in a younger population. The intraosseous lytic process can mimic tumor-like lesions such as aneurysmal bone cysts or metastatic malignancies.²⁰ Diagnosis of a pseudotumor is important to enforce earlier before attempting invasive diagnostic or surgical procedures such as biopsy, percutaneous drainage, or more aggressive surgery. Such intervention procedure mentioned above is contraindicated to be performed due to the risk of complications following such a procedure, such as life-threatening bleeding.²¹ In this patient, a biopsy or surgery was not performed because it was not indicated and increased the risk of bleeding.

Hemophilic pseudotumor occurs due to repeated episodes of bleeding at a bone fracture site, sub-periosteal hemorrhage, or bleeding into soft tissue caused by the absence or lack of effective replacement treatment.²² Patients with bleeding problems may be admitted to the hospital, especially in emergency and life-threatening settings. In hemophilia, the primary aim of care is to prevent and treat bleeding with the deficient clotting factor. Whenever possible, specific factor deficiencies should be treated with specific factor concentrates. Acute bleeds should be treated as quickly as possible, preferably within two hours. During an episode of acute bleeding, an assessment should be performed to identify the site of bleeding (if not clinically obvious), and appropriate clotting factor should be administered.³ A full evaluation, including lab work, CT scans, MRIs, and x-rays, can be performed.¹² Patients with more severe bleeding disorders may require prophylaxis for optimal hemostatic management, in addition to episodic hemostatic management for times of increased bleeding risk, such as with surgical procedures or with trauma, whereas children with mild bleeding disorders may only require episodic treatment.¹⁵ As hemorrhagic episodes are now well controlled with factor replacement therapy, the incidence of pseudotumor may have decreased. Among these patients, bleeding also tends to be more severe and varied in anatomical location.¹⁹

Where hemophilia is suspected based on a prolonged aPTT, it may be appropriate to administer fresh frozen plasma (FFP) while the results of appropriate factor assays are awaited.³ The current guidelines call for plasma transfusions in patients with coagulopathy only when a specific therapy or factor concentrate is not appropriate or is unavailable.²³ FFP contains approximately 200 units of FVIII coagulant activity in 150–300 ml volume, but it is difficult to reach FVIII levels higher than 30 IU/dL with FFP alone in hemophilia A.^24,25 In our center, back in 2024, to request FVIII laboratory examination, we have to request it from an external laboratory, which is not funded by the national insurance. Luckily, by 2025 our center can run the factor examination independently and included in the national insurance. In this case, the patient received an FFP transfusion before the factor VIII level result was obtained. Once the diagnosis is made, an appropriate dose of factor concentrate should be administered to achieve satisfactory factor levels.^26,27,28 Each unit of FVIII per kilogram of body weight infused intravenously will raise the plasma FVIII level approximately 2 IU/dL. The half-life of FVIII is approximately 8 to 12 hours. In this case, a patient with a maxillary hemophilic pseudotumor was treated as a head hemorrhage according to the guidelines. The target plasma FVIII level in patients with head hemorrhage is 50–80 IU initially and 30–50 IU for days 4–7 as a maintenance target.³ The patient started to get human plasma-derived factor VIII, 500 units/12 hours, intravenously for the first three days, followed by 250 units/24 hours intravenously until the 7th day. Until the end of observation, the patient was discharged from the hospital after the bleeding had been under control and finished serial Factor VIII injections for 7 days.

In clinical studies, baseline inhibitor measurements should be obtained as soon as treatment begins. In the presence of an inhibitor, as the most significant complication of hemophilia therapy, it could increase bleeding tendency, high FVIII consumption, lack of response or efficacy, decreased recovery, and decreased half-life.²⁹ In this case, the inhibitor was negative, the response to therapy was good, and the patient was discharged.

The best treatment for pseudotumor in patients with congenital coagulopathies is prevention, that is, proper long-term hematological treatment of muscle hematomas, until total resolution (reabsorption).¹⁷ In pediatric patients with severe hemophilia A, the World Federation of Hemophilia recommends early initiation of prophylaxis before joint disease, or ideally before the age of 3 years, to prevent spontaneous bleeding and breakthrough bleeding, including severe hemarthrosis, which can cause joint damage. Prophylactic administration of low-dose FVIII at 10 IU/kg, 2 times per week, is a recommendation for the management of hemophilia A in developing countries.^3,14 Mild to moderate bleeding episodes can be treated in a home setting. Protect, Rest, Ice, Compression, and Elevation (PRICE) may be used as the first aid for bleeding in muscles and joints before coagulation factor is given.¹⁴

In addition to coagulation factor concentrates, tranexamic acid is an antifibrinolytic agent that competitively inhibits the activation of plasminogen to plasmin and promotes clot stability. It is useful as adjunctive therapy in hemophilia and some other bleeding disorders.^3,24 Tranexamic acid is usually given as an oral tablet three to four times daily. It can also be administered by intravenous infusion two to three times daily and is also available as a mouthwash. Tranexamic acid is commonly prescribed for seven days.³ The dosage of tranexamic acid is 25 mg/kg per orally q 6–8 hours or 10 mg/kg intravenously q 6–8 hours.³⁰ We used tranexamic acid injection of 100 mg (~10 mg/kg BW) intravenously every 8 hours for 7 days of administration in this case. The pain management strategies for patients with hemophilia A are divided into three steps. The first step is using paracetamol/acetaminophen. The second step involves using either a COX-2 inhibitor (e.g., celecoxib, meloxicam, and others) or a combination of paracetamol/acetaminophen plus codeine (3–4 times/day) or paracetamol/acetaminophen plus tramadol (3–4 times/day). The third step involves morphine administration.³ This patient gets paracetamol to reduce pain.

This case was consulted with the Otolaryngology-Head and Neck Surgery department, and an open biopsy was advised. But after the diagnosis of hemophilia was made, the plan of biopsy was aborted. Treatment of HP is still challenging, especially in patients with large masses and extensive bone destruction. It depends on the lesion’s location and size, patients’ characteristics, and method of management. Most hemophilic pseudotumors require surgical intervention. Conservative treatment is suitable for superficial pseudotumor.²¹ If surgical extraction of the lesion is not feasible, radiotherapy and embolization of the pseudotumor have been utilized. Radiation therapy has been used as a single therapy or in combination with a factor. Radiation therapy has been recommended, especially in the presence of factor VIII inhibitors. If left untreated, hemophilic pseudotumor causes a plethora of complications. The mass effect of the progressively enlarging pseudotumor causes pressure on adjacent structures. Generalized complications of pseudotumor include hemorrhage, severe anemia, infection and septicemia, pseudotumor rupture, and even death.⁹ Given the rarity of HP, there is no consensus about specific management strategies.¹⁹ Different methods, like radiotherapy, surgical intervention, and factor VIII replacement, have been reported in the literature. Each method has its advantages and limitations.⁸ For this case, the patient had been given PRC transfusion, Factor VIII injection, tranexamic acid injection and consulted with the Otolaryngology-Head and Neck Surgery and Plastic Surgery departments for multidisciplinary team management.

This case highlights a rare but clinically significant presentation of hemophilia as a pseudotumor mimicking malignancy. Its strength lies in emphasizing a real-world diagnostic challenge, particularly in resource-limited settings where awareness and access to early diagnostic testing for bleeding disorders remain suboptimal. However, as a single case report, the findings are not generalizable and lack long-term outcome data.

In light of these considerations, hemophilia is a lifelong bleeding disorder that may present with rare complications such as hemophilic pseudotumor, particularly when diagnosis is delayed. This case illustrates how limited awareness can lead to misinterpretation as malignancy, exposing patients to unnecessary and potentially harmful interventions. Prompt recognition and appropriate factor replacement therapy are essential to control bleeding, reduce mass progression, and prevent avoidable complications.

We gave information for consent to the patient. The consent was written. The patient and the patient’s parents signed and agreed to be reported in a case report without receiving compensation.