FUS::CREM fusion is a distinct primary driver in rare neoplasms of the head and neck and other anatomic sites. Herein, we describe the clinicopathological, imaging, and molecular features of a malignant epithelioid mesenchymal neoplasm harboring FUS::CREM fusion, arising in the tongue of a 46-year-old male. Clinically, the patient presented with a left upper neck mass. Imaging revealed a 4.0 cm mass at the left base of tongue. Histologically, the tumor consisted of sheets of loosely cohesive, small round to ovoid cells with moderate cytoplasm, small nuclei with coarse chromatin, frequent nuclear pseudoinclusions, and dense peripheral lymphoplasmacytic and histiocytic infiltrates. Malignant features, including tumor necrosis, perineural invasion, and increased mitotic activity were observed; however, lymphovascular invasion was absent with no evidence metastatic disease in the examined lymph nodes. A comprehensive panel of immunohistochemical stains showed positivity for synaptophysin and ALK, with negative results for all other markers. RNA-based next-generation sequencing using anchored multiplex polymerase chain reaction (PCR) was performed and detected FUS::CREM fusion gene. The patient was treated by excision and postsurgical chemoradiation with no evidence of recurrence after four months. Additional cases supported by comprehensive clinical data collected over an extended period are necessary to precisely characterize epithelioid mesenchymal neoplasms harboring FUS::CREM fusion in the head and neck.

Ectomesenchymal chondromyxoid tumor (ECT) is a rare soft tissue tumor with peculiar histogenesis, exhibiting a predilection for the dorsum of the tongue. Molecular evidence suggests that it may originate from the migration of ectomesenchymal pluripotent cells from the neural crest to the tongue, where these cells may eventually proliferate and undergo myxoid and chondroid differentiation. This article illustrates a case of a 16-year-old female patient who presented with a nodule on the dorsum of her tongue, which had been present for four years. Surgical excision was performed, and histopathological analysis revealed a myxoid neoplasia composed of polygonal and spindle cells within a loose stroma containing chondroid areas. Tumor cells were positive for GFAP and S-100 proteins on immunohistochemical study, confirming the diagnosis of ECT. After a 5-year follow-up, the patient has shown no evidence of recurrence. Although rare, ECT can be diagnosed straightforwardly due to its distinctive clinical, histopathological, and immunohistochemical features. Clinicians and pathologists should become familiar with this tumor in order to avoid misdiagnosis.

METHODS: A healthy, 19-year-old woman was incidentally found to have a large, destructive tumor of T11 without neurologic symptoms. Biopsy demonstrated fibrocartilaginous mesenchymoma (FCM). The patient was treated with resection including subtotal corpectomy and T8-L1 fusion with use of cage and allograft strut construct. The patient remained without recurrence over 3 years of follow-up.
CONCLUSIONS: FCM arising from the spine is a rare tumor, of which this is the sixth report. FCM affects primarily young adults and is benign but locally aggressive, requiring complete excision to prevent recurrence.

Spinal phosphaturic mesenchymal tumor (PMT) is a rare disorder but can be cured once the diagnosis is clear and a complete removal by surgery is performed. To the best of our knowledge, only 22 cases in the spine have been described, and we report a case with the largest number of spinal segments (T12-L5) affected among spine PMT cases.
A comprehensive literature search was performed until May 23, 2023, following the Preferred Reporting Items for Systematic Reviews guidelines. Studies were chosen through relevant PubMed, Web of Science, and EMBASE searches to prioritize obtaining the largest studies. The Medical Subject Headings and Boolean operators employed for this search were (\"PMT\" or \"TIO\" or \"Tumor-induced osteomalacia\" or \"phosphaturic mesenchymal tumor\") and (\"spine\" or \"spinal\"). Two researchers (L.S.Z. and D.B.C) independently reviewed and evaluated the included articles. Any differing opinions were discussed until a consensus was reached. A total of 18 studies were included. A case report is also presented.
We report a case of spinal PMT. The full text of the relevant articles was construed. A total of 18 studies were reviewed and consolidated. These articles are roughly divided into the following 5 subcategories: 1) clinical features and baseline distribution, 2) laboratory and imaging findings, 3) pathological manifestations, and 4) surgical methods and treatment options.
Spinal PMT is very rare with a high rate of misdiagnosis and debilitating complications, so it is of significance to increase awareness of the disease among spine surgeons consulted by patients with spinal PMT. 68Ga-DOTATOC-PET/CT shows very high sensitivity to the spinal PMT but there is no way to exactly determine the location of the tumor. PMT has unique immunohistochemical characteristics and malignant PMT is rare. Once diagnosed, complete surgical excision is the recommended treatment. Burosumab is one of the available options, especially in cases that are recurrent and difficult to surgically resect.

BACKGROUND: Primary malignant cardiac mesenchymoma tumors are rarely described in the medical literature, with only a few published cases.
METHODS: We present a case of a primary malignant mesenchymoma in the left atrium extending to the left and right inferior pulmonary vein orifices, accompanied by mechanical obstruction of the mitral valve. The patient underwent surgical removal and radiotherapy.
CONCLUSIONS: Cardiac tumors are categorized as primary and secondary tumors. Primary cardiac tumors are extremely rare, with a low incidence rate of 0.001-0.28 %. Primary malignant tumors constitute less than 25 % of them. Malignant mesenchymoma is considered the rarest of them. These tumors proliferate and may cause metastases, making them highly malignant with a poor prognosis, especially if accompanied by metastases or invasion of nearby tissues.
CONCLUSIONS: The poor prognosis of cardiac mesenchymoma comes from the fact that it is aggressive and rapidly growing, which causes a rapid progression of mechanical symptoms and metastasis to nearby tissues, which makes it classified as a highly malignant tumor with a low survival rate. Surgical resection remains the mainstay of treatment, in addition to follow-up with chemotherapy or radiotherapy according to the grade of the disease, which was the case with our patient and the same as reported in previous literature. However, further research and case reports are needed better to understand the optimal management of this aggressive tumor.

磷酸盐尿性间叶性肿瘤是一种罕见的间叶性肿瘤，患者常伴有肿瘤相关性骨软化症，严重者可致残疾，绝大部分患者肿瘤完整切除后可治愈。该病镜下组织形态多样，可与多种间叶性肿瘤重叠，极易误诊。本文报道1例罕见的原发于颅内的磷酸盐尿性间叶性肿瘤，患者伴有低磷血症及骨软化症，镜下主要由温和的短梭形及卵圆形细胞组成，间质内见大量增生的毛细血管及散在厚壁血管，可见散在成熟脂肪细胞小灶。本例经过充分取材，并未发现特征性絮状钙化及破骨样巨细胞。.

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm causing tumor-induced osteomalacia (TIO) and is characterized by secretion of FGF23, renal phosphate wasting and hypophosphataemia. It can be completely cured by resection and therefore its diagnosis is of utmost importance. Although the histology is well described, there is sparse literature on cytology of PMT and only three cases have been described so far. A 45-year-old lady presented with a non-tender mass in hard palate for 2 years from which fine-needle aspiration was done. The smears were paucicellular and showed bland spindle cells embedded in osteoid-like stromal matrix in a hemorrhagic background. Here we take the opportunity to describe the cytological findings of PMT along with its cytological differentials and a summary of prior published cases.

BACKGROUND: A biliary inflammatory myofibroblastic tumor (IMT) is a rare type of mesenchymoma that, although it has a broad age spectrum, usually occurs in adults. Diagnosis is difficult because biliary IMTs often exhibit nonspecific clinical symptoms and imaging features, resulting in delayed or inappropriate treatment. Although most IMTs are benign, some show malignant properties such as infiltration, recurrence, and metastasis.
METHODS: Here, we retrospectively describe a 10-month-old infant who was admitted to our hospital due to stubborn jaundice. The patient responded poorly to routine medical treatment and his clinical manifestations and laboratory tests lacked specificity, so we turned to repeated ultrasound scans and other imaging examinations. As both hepatosplenic ultrasonography and diffusion-weighted magnetic resonance imaging demonstrated a space-occupying lesion, an exploratory laparotomy was performed. The final diagnosis made over two mo after the disease onset was infant biliary cirrhosis caused by a biliary IMT, which partially infiltrated into the liver. This infant is the youngest case of biliary IMTs that has been reported till now. The patient underwent an incomplete resection of the mass and Kasai Portoenterostomy. However, because of cirrhosis, he also received a paternal liver transplant. Since some IMTs show malignant properties, we proceeded with a three-year of follow-up; however, no recurrence or metastasis has been noted.
CONCLUSIONS: Neoplastic disease such as IMTs should be considered when routine medical treatment of obstructive jaundice is not successful. Observation of dynamic imaging changes is helpful for diagnosis. Periodic follow-up is necessary for IMTs.

Most osteomalacia-inducing tumors (OITs) are phosphaturic mesenchymal tumors (PMTs) that secrete fibroblast growth factor 23 (FGF23). These tumors usually occur in the bone and soft tissues, and intracranial OITs are rare. Therefore, intracranial OIT is difficult to diagnose and treat. This paper presents a case of intracranial OIT and shows a review of previous cases. A 45-year-old man underwent nasal cavity biopsy and treatment with active vitamin D3 and neutral phosphate for hypophosphatemia. Amplification of FGF23 mRNA level within the tumor was detected. Subsequently, the surgical specimen was diagnosed with a PMT and was considered the cause of the patient\'s osteomalacia. The patient was referred to a neurosurgery department for the excision of the intracranial tumor extending to the nasal cavity. After tumor removal, the serum levels of FGF23 and phosphorus were normalized as compared to preoperative those. The patient remains disease-free, without additional treatment, approximately 10 years after surgery, with no tumor recurrence. As per the literature, intracranial OITs usually occur in patients aged 8-69 years. Bone and muscle pain are major complaints. Approximately 60% of the patients reported previously had symptoms because of intracranial tumors. In some cases, it took several years to diagnose OIT after the onset of the osteomalacia symptoms. Laboratory data in such cases show hypophosphatemia and elevated FGF23 levels. Because FGF23 levels are associated with the severity of osteomalacia symptoms, total tumor resection is recommended. PMT and hemangiopericytoma (HPC) are histologically similar, but on immunochemistry, PMT is negative for signal transducer and activator of transcription 6 (STAT6), whereas HPC is positive. FGF23 amplification is seen in PMTs but not in HPCs. Therefore, the analysis of FGF23 and STAT6 was helpful in distinguishing PMTs from HPCs. In cases of hypophosphatemia and osteomalacia without a history of metabolic, renal, or malabsorptive diseases, the possibility of oncogenic osteomalacia should be considered.

Nasal chondromesenchymal hamartoma (NCMH) is a very rare, benign sinonasal tract tumor commonly affecting infants. In this paper, in addition to presenting a systematic review of the literature on NCMH, we also report an unusual case of NCMH in an adolescent patient. A systematic review conducted following the PRISMA guidelines. PubMed, EMBASE and manual search through references of relevant publication were utilised to gather all published case-reports of NCMH. Data collected from each case-report for patient demographics, site and size of NCMH, clinical presentation, co-morbidities, diagnostic methods, treatment options and follow-up methods. The systemic review collected sixty-two case-reports of NCMH (including our case) affecting 42 men and 21 women (2:1 male to female ratio). Mean average age was 5.1 years (age range: 1 day to 70 years). The anatomical sites of the tumor were: nasal cavity (n = 17), paranasal sinuses (n = 30), orbital region (n = 17), and the base of the skull (n = 16). The reported clinical manifestations were nasal obstruction or congestion (n = 29), nasal mass (n = 27), epistaxis (n = 6), orbital symptoms (n = 14). NCMH is a very rare cause of nasal masses in infants and toddlers. Our case and previous case reports confirm that NCMH can mimic other benign and malignant tumors, therefore we should be vigilant for rare pathologies that lead to nasal masses. Recently the link between DIECR1 mutation with NCMH has been established, so NCMH should be considered in any patient with nasal or orbital symptoms with a history of DICER1-related tumor spectrum.