Hyperostosis Frontalis Simulating Metastatic Deposits: Unmasked on SPECT-CT.

Skeletal scintigraphy has a pivotal role in detecting a number of bone pathologies, but it has its own limitations because of 2D image acquisition. Hybrid imaging acts as a savior in these cases where it is difficult to distinguish between benign and malignant lesions just on the basis of planar images. We present one such case of known breast carcinoma with abnormal increased radiotracer uptake in the skull which was difficult to characterize as benign lesion such as hyperostosis frontalis or metastatic osseous lesion. The importance of describing this case is to have a thorough understanding of hyperostosis patterns and to not confuse it with metastatic deposits in patients with known malignancies.

Morpho-radiological and brain endocast analysis in the study of Hyperostosis Frontalis Interna (HFI): A combined approach.

The purpose of this study is to anatomically evaluate the impact on the patient intra vitam of an endocranial condition on a late 20th century skull housed in the Section of Legal Medicine of the University of Foggia (Foggia, Apulia, Italy). After performing a retrospective diagnosis, the condition is framed in the broader context of studies on this pathology. An anthropological and radiological analysis (X-ray and CT scan imaging) made it possible to confirm the preliminary information and to detail the osteological diagnosis of HFI. In order to assess the impact on the cerebral surface of the endocranial growth a 3D endocast was obtained using the Software OrtogOnBlender. The skull is demonstrated to have belonged to a female senile individual known, from limited documentary evidence, to have suffered from a psychiatric condition during her life. The final diagnosis is hyperostosis frontalis interna (HFI), Type D. Although a direct correlation between the demonstrated intracranial bony growth and the onset of the patient's psychiatric condition is difficult to retrospectively ascertain, the pressure exerted on this female individual's frontal lobe may have contributed to further degenerative behavioural changes in the last years of her life. This case adds to previous knowledge, especially from the palaeopathological literature, on this condition and, for the first time, presents a neuroanatomical approach to assess the global impact of the disease.

"Skull on Fire": Monostotic Paget Disease of the Skull Bone.

An 81-year-old woman was evaluated for a stroke. CT showed no intracranial abnormalities but diffuse patchy aspect of the neurocranium. An MRI and F-NA PET/CT were performed to differentiate between metastases, Paget disease, hyperostosis frontalis interna, and primary malignancy. MRI yielded no additional findings. F-NA PET/CT showed diffusely increased uptake in the skull and 4 spots with intense uptake. No other suspicious skeletal foci were seen elsewhere. Low-dose CT showed no sign of malignancy elsewhere. Image findings together with elevated serum alkaline phosphatase levels, slightly increased calcium levels, and normal phosphorus levels were interpreted as pathognomic for monostotic Paget.

A rare case of hyperostosis frontalis interna in an 86-year-old Japanese female cadaver.

Hyperostosis frontalis interna (HFI) is a condition characterized by abnormal bone outgrowth on the inner surface of the frontal bone. Most HFI cases occur in post-menopausal elderly women. The pathology of HFI development is uncertain. The estimated incidence of HFI ranges from 5 to 12% in Western countries, but few cases have been reported in the Japanese population. Here, we report a case of HFI in an 86-year-old Japanese female cadaver. Macroscopically, the internal surface of the frontal bone exhibited bilateral nodular protrusion with sparing of the midline, while the external surface was normal. According to the morphological classification of HFI proposed by Hershkovitz et al. this case belongs to type D, the most severe type. Using computed tomography (CT), we defined five layers, designated as I-V from the inner to the outer layer, in the nodular region of HFI; however, the normal frontal bone is composed of three layers. Histological results demonstrated that layers I, III, and V consisted of the cortical bone, and layers II and IV consisted of the trabecular bone. We also observed increases in the numbers of lamellar bone and blood vessels on the dural side of layer I, indicating increased vascularization and active osteogenesis. These results indicate that layer II represents a new diploe within the inner table, which split into layers I and III, suggesting that diploization within the inner table by activated remodeling may be involved in the development of hyperostosis in this case.

Comparative Analysis of Femoral Macro- and Micromorphology in Males and Females With and Without Hyperostosis Frontalis Interna: A Cross-Sectional Cadaveric Study.

We hypothesized that subjects with hyperostosis frontalis interna (HFI), which represents local, endocranial thickening of the frontal bone, would express extra-calvarial manifestations of this condition. Therefore, we compared femoral bone mineral density, geometry, and microarchitecture of males and females with HFI to those without this condition as well as between males and females with HFI. The sample was taken from human donor cadavers, 38 males (19 with and 19 without HFI) and 34 females (17 with and 17 without HFI) that were age-matched within the same sex. The specimens of femoral bones were scanned using microcomputed tomography and dual-energy X-ray absorptiometry (DXA). Parameters of hip structure analysis (HSA) were calculated from data derived from DXA scans. Females with HFI had increased cortical bone volume fraction and their cortical bone was less porous compared to females without HFI. Males with HFI showed microarchitectural differences only with the trabecular bone. They had increased bone volume fraction and decreased trabecular separation compared to males without HFI, although with borderline significance. These microarchitectural changes did not have significant impact on femoral geometry and bone mineral density. The same, still unknown etiological factor behind HFI might be inducing changes at the level of bone microarchitecture at a remote skeletal site (femoral bone), in both sexes. These alterations still do not have the magnitude to induce obvious, straightforward overall increase of bone mineral density measured by DXA. HFI could be a systemic phenomenon that affects both males and females in a similar manner.

Micro-computed Tomography Study of Frontal Bones in Males and Females with Hyperostosis Frontalis Interna.

Hyperostosis frontalis interna (HFI) represents irregular thickening of the endocranial surface of the frontal bone, mostly seen in postmenopausal females. The microarchitecture of this condition is poorly studied. The aim of this cross-sectional autopsy study was to investigate and compare microarchitectural structure of the frontal bone affected with HFI in both sexes and to test whether HFI severity could be distinguished at the microarchitectural level. The sample was taken from human donor cadavers, 19 males (61 ± 15 years old) and 17 females (75 ± 15 years old). After classification of HFI severity (type A, B, C or D), samples of the frontal bone were taken and scanned using micro-computed tomography. Bone volume fraction was higher and total porosity lower only in the outer table of males with HFI, compared to females with HFI. Mean total sample thickness differed only between males with HFI type A and D. Bone microarchitecture between males and females with corresponding HFI types (e.g., male with type A versus female with type A) differed only in HFI type C regarding the fractal dimension of diploe. The degree of anisotropy differed between HFI subtypes in males, but the post hoc analysis revealed no significant differences between individual groups. Other microarchitectural parameters did not differ among males with different HFI subtypes, as well in females, in any part of the frontal bone. There is no difference in microarchitectural structure of the frontal bone between males and females with HFI, in general aspect and within corresponding HFI subtypes. HFI severity could not be distinguished at the microarchitectural level, neither in males nor in females.

Radiological evaluation of Hyperostosis frontalis interna: is it of clinical importance?

Hyperostosis frontalis interna (HFI) presents irregular thickening of the frontal bone. Even though HFI is frequently seen during routine radiological imaging, it usually remains unrecorded owing to a common belief that it just represents an incidental finding or anatomical variant. Recent studies implied that HFI may be clinically relevant. Etiology of HFI is still debated, while presumptions are mainly based on altered sex steroids impact on skull bone growth. Some authors implied that frontal bone might be particularly affected by this condition due to specificity of its underlying dura. In this paper we present a 27-years old female patient with a treatment resistant headache. Head CT showed massive, irregular bony mass, with lobulated contours arising from the right frontal bone, but did not cross the fronto-parietal suture, spearing the superior sagittal sinus and skull midline. After surgery, histopathological analysis of the frontal bone sample in our patient showed thickening pattern similar to those described in micro-CT studies of HFI. Furthermore, in an attempt to test speculation of the possible role of estrogen in pathogenesis of HFI, we investigated the expression of α-estrogen receptors on dura of the frontal region. These analyses confirmed nuclear expression of estrogen on frontal region dural tissue, supporting previous speculation of the development mechanisms of HFI and contributing to a better understanding of this common condition of the frontal bone. Additionally, the presence of HFI may result in severe symptomatology, which could be misinterpreted and related to other disorders if HFI is not radiologicaly recognized and reported.

Hyperostosis frontalis interna and frontal bone thickness among various age groups - differences between males and females.

Hyperostosis frontalis interna (HFI) represents an abnormality of the frontal cranial bone that is characterized by bilateral, nodular thickening of its inner lamina and may sometimes be associated with neuropsychiatric symptoms such as headaches and depression. The aim was to assess prevalence, sex and age differences of HFI and frontal bone thickness by means of MRI. This retrospective study included 908 subjects who were divided into male and female groups and further subdivided into three groups, youngest (≤45 years), middle-aged (46- 65 years) and the oldest group (65 years). The thickness of the frontal bone was measured on the T2-weighted axial images at the top level of the lateral ventricles as a mean from both sides. We considered 10mm or thicker frontal bone as HFI. The total prevalence of HFI was 8.1%, with a more frequent occurrence in women (p0.05). In males, there was no difference in the frontal bone thickness between different age groups (p0.05), while in females we found differences between the youngest and the oldest group, and also between the middle-aged and the oldest group (p0.05). The female respondents had a thicker frontal bone, which was statistically significant only in the oldest group (p0.001). Frontal bone thickness was age-dependent only in women (Spearman's Rho 0.11; p≤0.01). In women, unlike in men, there is an age-related progression of HFI with increasing prevalence, with 16.4% occurrence in the oldest group.

Radiological diagnostic features of uremic leontiasis ossea: a case report.

Uremic leontiasis ossea (ULO), which occurs in the craniomaxillofacial region, is a sign of terminal stage osteitis fibrosa cystica or brown tumors and primarily caused by secondary hyperparathyroidism induced by renal failure. Pathophysiological changes include osteoclasts or osteoblasts proliferation, bone resorption, bone decalcification, and connective tissue proliferation. In this paper, we report a case of a 24-year-old female patient, who was diagnosed with ULO and presented with multiple facial swellings. Imaging features included zonal patterns with alternating rings of hypo- and hyperattenuated craniomaxillofacial bones, and diffused mixed sclerotic tissues with lytic changes in CT imaging. T1 weighted image and T2 weighted image in MRI were characterized by alternating rings of low and intermediate signal intensity patterns. To the best of our knowledge, this case is the first example of pathologically proved ULO with maxillofacial MRI.

Frontal Sinus Osteoma Accompanied by Intracranial Mucocele and Local Hyperostosis Frontalis Interna.

Frontal sinus osteoma accompanied by intracranial mucocele and local hyperostosis frontalis interna has never been reported. A 47-year-old woman presented with a 3-month history of intermittent headache. Physical examination revealed no neurologic abnormality. Contrasted magnetic resonance imaging showed a frontal heterogeneously enhanced lesion with adjacent nonenhanced cyst. Computed tomography showed a bone density mass, which was accompanied by local hyperostosis frontalis interna, which filled the left frontal sinus and extended intracranially. The patient underwent a left frontobasal craniotomy. Both the osseous mass and cyst capsule were removed totally via a frontal craniotomy, followed by skull base reconstruction. The postoperative course was uneventful. The final pathologic diagnosis was osteoma and mucocele.

Brain Metastases Mimicking Hyperostosis Frontalis Interna on 99mTc HDP Bone Scintigraphy.

Symmetric bifrontal uptake of bone-seeking agents is usually considered as the main feature of hyperostosis frontalis interna in postmenopausal elderly women. This finding is not uncommon in elderly women because of the change in their hormonal level. However, in the present case, a 66-year-old woman with intra-axial brain metastases of breast cancer showed symmetric bifrontal uptake on bone scintigraphy. Therefore, symmetric bifrontal uptake should not always be considered as a definite indicator of hyperostosis frontalis interna. Further evaluation such as SPECT/CT is needed for evaluation of brain metastases especially in cancer patients.

Uremic Leontiasis Ossea in a Patient With Chronic Renal Insufficiency Demonstrated on Bone Scintigraphy.

A 37-year-old woman with chronic renal insufficiency underwent bone scintigraphy to evaluate renal osteodystrophy (ROD). Markedly increased uptakes were shown in the maxilla and the mandible, which suggested extensive maxillary and mandibular hypertrophy. CT image revealed that diffuse bony thickening and ground-glass appearance in the skull, maxilla, and mandible with poor distinction of the corticomedullary junction. Whole-body bone scintigraphy images also demonstrated various skeletal characteristics of ROD. This case emphasizes the utility of bone scintigraphy for the surveillance of the whole body in ROD.

Hyperostosis frontalis interna in postmenopausal women-Possible relation to osteoporosis.

To improve our understanding of hyperostosis frontalis interna (HFI), we investigated whether HFI was accompanied by changes in the postcranial skeleton. Based on head CT scan analyses, 103 postmenopausal women were divided into controls without HFI and those with HFI, in whom we measured the thickness of frontal, occipital, and parietal bones. Women in the study underwent dual energy x-ray absorptiometry to analyze the bone density of the hip and vertebral region and external geometry of the proximal femora. Additionally, all of the women completed a questionnaire about symptoms and conditions that could be related to HFI. Women with HFI had a significantly higher prevalence of headaches, neurological and psychiatric disorders, and a significantly lower prevalence of having given birth. Increased bone thickness and altered bone structure in women with HFI was localized only on the skull, particularly on the frontal bone, probably due to specific properties of its underlying dura. Bone loss in the postcranial skeleton showed the same pattern in postmenopausal women with HFI as in those without HFI. Recording of HFI in medical records can be helpful in distinguishing whether reported disorders occur as a consequence of HFI or are related to other diseases, but does not appear helpful in identifying women at risk of bone loss.

Dramatic alteration of the skull in a uremic patient with leontiasis ossea.

The craniofacial skeleton represents a peculiar target of hyperparathyroidism in patients with end-stage renal disease who exhibit a dramatic pattern of uremic leontiasis ossea. Scant information regarding this condition is available in the renal literature, as the extreme and typical manifestations of leontiasis ossea have been described in only a small series of patients. We herein report a case of significant amelioration of massive modification of the facial appearance of a 30-year-old uremic Chinese woman with severe skeletal deformities who underwent total parathyroidectomy with a forearm autograft concurrently with effective drug treatment. This report may shed light on how to better understand and treat this metabolic derangement.

Computed tomography and magnetic resonance imaging of maxillofacial lesions in renal osteodystrophy.

PURPOSE: This study aims to describe the computed tomography (CT) and magnetic resonance (MR) imaging appearance of maxillofacial lesions in renal osteodystrophy. PATIENTS AND METHODS: We retrospectively reviewed the CT and MR imaging of maxillofacial region in 9 patients (6 females and 3 males with mean age of 31 yr) with renal osteodystrophy. They presented with facial swelling (n = 6), facial disfigurement (n = 2), and oral cavity mass (n = 1). They underwent CT and MR imaging of the maxillofacial region. RESULTS: Brown tumors (n = 6) were seen in the mandible (n = 4) and maxilla (n = 2). They appeared as mixed lytic and sclerotic (n = 4) and sclerotic (n = 2) lesions at CT. The lesions appeared as hypointense at T1-weighted images and of mixed signal intensity at T2-weighted images with intense contrast enhancement (n = 6). Uremic leontiasis ossea (n = 2) appeared at CT as diffuse hyperostosis with protruded maxilla and obliterated sinus. At MR imaging, there was expansion of the maxilla with obliteration of the maxillary sinuses and protrusion of the mandible. The lesion exhibited low signal intensity at T1-weighed images. At T2-weighted images, the lesion showed low signal intensity with small hyperintense lesions. Dystrophic calcification (n = 2) was seen in the parotid and the check. CONCLUSION: We concluded that CT and MR imaging are helpful for diagnosis and treatment planning of maxillofacial lesions of patients with renal osteodystrophy.