Rapidly growing sinus pericranii within a short period: a case report

Sinus pericranii (SP) is a rare vascular malformation characterized by abnormal communication between the intracranial and extracranial venous systems [1]. Sinus pericranii is most commonly seen in the distribution areas of the superior sagittal and transverse sinuses [2]. There are no uniform criteria for the etiology, pathogenesis, diagnostic criteria, treatment options, or prognosis of sinus pericranii [3]. In this paper, we present the diagnosis and treatment of a child admitted to our neurosurgery department in 2019 with rapidly growing frontal sinus pericranii, as well as the 3-year postoperative follow-up. The authors summarize the clinical presentation characteristics, diagnosis and treatment methods, and prognosis of this disease using relevant domestic and international literature to improve clinicians’ understanding of this disease. It is rare to see a significant growing of the sinus pericranii within a short period, and the mechanism of their occurrence needs to be further explored.


Introduction
Sinus pericranii (SP) is a rare vascular malformation characterized by abnormal communication between the intracranial and extracranial venous systems [1]. Sinus pericranii is most commonly seen in the distribution areas of the superior sagittal and transverse sinuses [2]. There are no uniform criteria for the etiology, pathogenesis, diagnostic criteria, treatment options, or prognosis of sinus pericranii [3].We present the diagnosis and treatment of a child admitted to our neurosurgery department in 2019 with rapidly growing frontal sinus pericranii, as well as the 3-year postoperative follow-up.The authors summarize the clinical presentation characteristics, diagnosis and treatment methods, and prognosis of this disease using relevant domestic and international literature to improve clinicians' understanding of this disease.

Clinical course
We describe a case of SP in a 10-year-old girl who was noted to have frontal scalp swelling at birth that significantly increased within 6 months. After the child was born, her parents noticed that the forehead swelling appeared when the child cried. The mass was peanut-sized, soft, with normal skin on its surface. When the child was quiet, it vanished on its own. In the past 6 months, the swelling was found to be rapidly growing, occasionally accompanied by headache and local tenderness, so the child came to our hospital for consultation. The child's parents denied any history of head trauma within the last decade.

Physical examination and imaging studies
The results of the sense system examination were normal. The motor system examination revealed that her muscle strength was normal (grade 5) and her movements were coordinated. A 5 cm by 8 cm mass was discovered beneath the scalp of the patient's forehead in the prone position. It was soft, compressible, non-pulsatile, and non-translucent. Its size varied with the child's position. The mass increased significantly in the prone position and during the Valsalva 1 3 maneuver and disappeared in the lying, sitting, and standing positions (Fig. 1). There was no dilated draining vein in the surrounding scalp, and palpation revealed local tenderness with head pain. The cranial CT showed a thickening of the subscalp soft tissue in the frontal area with tortuous vascularity (Fig. 2a). MRI showed a lesion located in the subscalp soft tissue in the midline of the forehead, in the form of flattened bumps with well-defined borders. T1W showed a low signal (Fig. 2b), and MRV indicated that the lesion communicated through at least one malformed vessel and a thickened superior sagittal sinus (Fig. 2c). The presence of a massive mass of malformed venous vessels on the forehead was revealed by DSA (Fig. 2d). To evaluate the surgical risk of the patient, a preoperative 3D CT was performed, which showed the presence of partial bony destruction in the forehead and two holes that could be seen in the forehead as indicated by the arrows (Fig. 2e). The child's guardian requested surgical treatment considering the impact of the lesion on the appearance and the possibility of its progression.

Operation
A coronal incision was made within the hairline that allowed adequate exposure of the lesion. After the excision of the scalp layers, the flap was freed, and the periosteum was incised at the edge of the sinus pericranii. The periosteum was peeled off along the skull, where multiple pressure marks on the skull were visible and at least two veins were visible communicating with the skull through the bone holes. The bone foramen was closed with bone wax after electrocoagulation, and then the lesion was completely stripped from the capitellum. Postoperative CT imaging showed that the lesion has been removed (Fig. 2f). HE staining shows malformed vessels of various sizes with thin and thick walls and partial thrombosis (Figs. 3 and 4).

Postoperative follow-up
The child recovered well with no recurrence at the outpatient follow-up 1 month after surgery ( Fig. 5a-b). At the outpatient follow-up 3 years after surgery, there was no recurrence, no headache, and no local pain symptoms (Fig. 5c).

Discussion
Sinus pericranii was first described by Hecker in 1845 and was officially named by Stromeyer in 1850. The etiology of sinus pericranii is unclear.
It is generally agreed that congenital developmental malformations, trauma, surgery, and syndromes caused by certain genetic mutations can lead to their occurrence [3]. A varicose malformation venous vascular mass is thought to develop on the exterior of the skull as a result of the sinus pericranii, which arises from the intracranial venous sinus and drains through diploic veins below the cap aponeurosis (Fig. 6).
Sinus pericranii is more common in children and adolescents [3]. The typical clinical manifestation of sinus pericranii is a reversible subscalp mass of variable size, soft, and non-pulsatile, with a negative transillumination test and normal skin color and temperature on the surface of the mass. It appears when lying flat and lowering the head and shrinks or disappears when raising the head and standing, increases when compressing the jugular vein or performing Valsalva maneuvers, and shrinks when squeezing [4]. Most of the lesions were located in the frontoparietal region, close to the midline region, frontal (43%), followed by parietal (36%) and occipital (7.4%). The lesion in this patient was located in the midline region of the forehead [5]. The sinus pericranii may exist independently or in combination with other malformations, including hypoplasia of the intracranial venous sinus, nonsyndromic or syndromic craniosynostosis, and hydrocephalus [6]. As reported by Marco Pavanello, while the natural history of sinus pericranii remains unclear, most cases remain stable in the long term [2]. However, it is rare to see a significant increase in the volume of the sinus pericranii with headache and local tenderness within 6 months in this patient. In this case, there are several possible reasons for the significant short-term enlargement of the lesion: the growth phase, the neglected history of trauma, and the expression of abnormal genes. Combined with imaging and surgical findings, the headache and local tenderness may be related to the communication between the intracranial vein of the sinus pericranii and the superior sagittal sinus, which may lead to poor drainage of the superior sagittal sinus and increased pressure in the intra-sagittal vein when the head is lowered, strained, coughing, etc., causing a headache.
Radiographic examination of the sinus pericranii of the skull includes (1) cephalometric X-ray, which may (4) The lesions are honeycomb-like or hypointense on MRI T1-weighted imaging, and isointense or hyperintense on T2-weighted imaging, after which the lesions are enhanced significantly, and may show whether it is combined with other intracranial malformations. Intracranial venous sinus development and intra-and extracranial communication can be assessed by magnetic resonance venography; (5) the whole brain angiography venous phase shows extracranial veins connected to the intracranial dural sinuses by dilated platysmal veins [2,[5][6][7].
There are still no clear diagnostic criteria for the diagnosis of sinus pericranii. The diagnosis is usually clear based on typical clinical symptoms, signs, and ancillary examinations, but it should be differentiated from the meningeal bulge, dermatomal cyst, and epidermoid cyst. Treatment of sinus pericranii includes: 1. Conservative treatment and follow-up observation [8,9]: A small number of sinus pericranii may regress on their own with growth and development, necessitating close attention to the change in lesion volume and skull damage. It has been reported that the symptoms are relieved in some patients after taking oral drugs. However, the sample size is small, so its effectiveness needs further research and exploration. 2. Surgical resection: It is currently the treatment of choice for those patients with an affected appearance, a larger lesion size, larger local skull defects, a greater risk of rupture and infection, or a strong desire for surgery. Surgical procedures focus on the excision of the malformed aberrant vascular network, occlusion of the damaged skull, and treatment of the malformed vessels if necessary to allow intracranial communication. Most patients have undergone surgical treatment with excellent outcomes, but some are at risk of recurrence. Studies have shown that the size of the abnormal vascular network, the degree of skull destruction, and the presence of malformed vessels in the intracranial coarse communication are important factors for postoperative recurrence [5,6]. 3. Endovascular treatment [7]: Treatment is achieved by embolization of the abnormally communicating vessels or injection of sclerosing agents. Endovascular approaches to the treatment of SP are less invasive than surgical procedures but carry risks of skin necrosis and intracranial venous embolism.

Conclusion
Sinus pericranii is a rare disease, mostly seen in children and adolescents, and the lesions are mostly located in the top frontal area near the midline. There are currently no clear diagnostic criteria, and the diagnosis is usually confirmed on the basis of typical clinical symptoms, signs, and ancillary findings. Depending on the condition, follow-up observation, surgical resection, endovascular treatment, and The mechanism diagram of sinus pericranii pharmacological treatment are available. With appropriate therapeutic measures, patients with sinus pericranii can achieve good outcomes. Rapidly enlarging sinus pericranii in the short term has not been reported, and the mechanism of their occurrence needs to be further explored.
Author contribution Dr. Yuchen Sun: study concept and design, participation in surgery, manuscript writing. Dr. Binglei Wang: outpatient follow-up. Dr. Huijuan Wang: critical revision of the manuscript.
Funding This study was supported by the Natural Science Foundation of Hebei Province, China (Grant No. H2022206078).

Data availability
The data used to support the findings of this study are available from the corresponding author upon request.

Declarations
Ethical approval This study complies with all institutional guidelines regarding human subjects.

Consent to participate
Informed consent was obtained from the patient's guardian.