Cranial Fasciitis in Children: Expanding the Spectrum of USP6-Associated Clonal Transient Neoplasms

Background: Cranial fasciitis (CF) is a benign (myo)fibroblastic proliferation of children. Typical presentation consists of a rapidly growing solitary mass on the temporal or parietal cranium in the first 2 years of age. CF is characterized by a rapid growth followed by a relative slowdown and even growth arrest. The finding of somatic USP6 gene rearrangements demonstrating clonality in CF together with its clinical behavior places it in the category of diseases recently termed “transient neoplasia.” Methods: Histological, immunohistochemical, and molecular findings of 18 patients with CF were retrospectively studied. Results: The tumor typically presented as a painless rapidly enlarging mass in the temporal region. Sixty-six percent of the cases harbored USP6 gene rearrangement. Nine patients were treated with gross total resection (GTR) and 9 with subtotal tumor resection (STR). Two patients treated with GTR had recurrence. Five patients treated with STR had progression-free disease for at least 10 months after surgery and in four patients the tumor regressed spontaneously a median 16 months after surgery. Conclusions: In this largest series to date, we reported the clinicopathological, immunohistochemical, and molecular findings of 18 pediatric cases of CF with emphasis on the clinical growth pattern of these tumors.

1068 Cranial Fasciitis of the Temporal Bone

We present the case of a child with a rare benign tumour of the temporal bone. A nine-month-old girl was referred to her local paediatric hospital with a painless right-sided, post-auricular swelling increasing in size in the preceding two months. On examination there was a 2x2cm mass overlying the temporal bone posterior to the right ear. The mass was firm, immobile, non-tender and well circumscribed. Ultrasound demonstrated a 1.9cm subcuticular mass with evidence of intracranial extension through the suture. Vascular flow and hyperechoic foci were demonstrated within the lesion. The local paediatric team requested magnetic resonance imaging (MRI) and computed tomography (CT) of temporal bone prior to referral to tertiary care centre. Imaging displayed a 2cm expansile lesion of the temporal bone with cortical loss and effacement of underlying dural venous sinus. The patient proceeded to incisional biopsy for tissue diagnosis which was suggestive of cranial fasciitis. Following discussion at the regional multidisciplinary meeting, she underwent surgical excision of the tumour in a joint Neurosurgery/Otology case. The tumour was fully resected macroscopically, with the normal surrounding bone and mastoid air cells preserved. Final histopathology showed a highly cellular lesion composed of spindle cells arranged in fascicles, with areas of myxoid background and confirmed the tumour to be cranial fasciitis. The child has made a good recovery and will be kept under close clinical follow-up. This case demonstrates a rare benign tumour of the temporal bone that may present to an otolaryngologist and the importance of tissue diagnosis, imaging and multidisciplinary management.

A Novel Therapeutic Approach for Cranial Fasciitis Utilizing Frameless Stereotaxy

Cranial fasciitis is a rare cause of a painless, progressive skull mass in the pediatric population, having been described in only 80 cases in the literature to-date. While the etiology remains unknown, the pathogenesis is thought to be a reactive process causing a non-neoplastic fibroblastic proliferation arising from the deep fascia or periosteum of the cranium. Accurate diagnosis may be delayed due to the lack of physical signs and symptoms on presentation, as well as equivocal imaging for the other lesions included in the differential diagnosis. Importantly, in the case of cranial fasciitis, involved tissue is hard to decipher from normal tissue in the cranium, and margin recommendations have not yet been made clear in the current literature. Herein, we present a case of confirmed cranial fasciitis in a 2-year-old female patient in whom frameless stereotaxy was used intraoperatively to determine the extent of the lesion and ensure adequate resection and minimize recurrence risk.

A Novel COL1A1-CAMTA1 Rearrangement in Cranial Fasciitis

Cranial fasciitis is an uncommon benign fibroblastic tumor, generally histologically identical to nodular fasciitis. It develops almost exclusively in children. Cranial fasciitis manifests clinically as a painless rapidly growing solitary nodule in the head and neck area, frequently eroding the underlying bone. Thus, this entity is often confused with aggressive lesions such as sarcomas, both clinically and radiologically. Histopathologic examination is essential to differentiate between cranial fasciitis and fibrohistiocytic or even sarcomatous lesions observed in children. In this article, we present a case of cranial fasciitis with intracranial extension in a 2-year-old boy. Although USP6 rearrangement has recently been recognized as a recurring alteration in nodular fasciitis, we present a novel COL1A1-CAMTA1 fusion in this lesion.

Infantile cranial fasciitis

Cranial fasciitis (CF) is a rare benign lesion of the skull. Due to the rarity of this disease, prospective studies of it have not been conducted. The first description dedicated of the case of CF was in 1980. Later were descriptions of only clinical cases of observation and treatment of children with this pathology. For these reasons, questions regarding true incidence, genetic risk factors, prognosis and long-term still unanswered. Clinically, CF is represented by a dense, painless, growing mass on the scalp. Given the rarity of the occurrence of CF in differential diagnosis, it is usually not considered. In addition, there are no pathognomonic clinical signs and symptoms, and changes on MRI are often non-specific. Treatment involves removal of the tumor mass, after which a histopathological examination confirms the diagnosis of CF. As a rule, a good result is observed with complete resection, however, in this case it has to necessary to perform auto-bone grafting of the skull bone defect. CF is a rare and underexplored fibroproliferative disease. Because of its locally invasive nature and nonspecific manifestations of CF, it is often difficult to distinguish from malignant neoplasms and infections. Complete surgical removal is the best choice to make diagnosis and successful treatment. Parents gave their consent to use information about the child in the article.