Benign fibrous histiocytoma of bone

Nonossifying Fibroma Involving Epiphysis of Long Bone-Case Report and Review of the Literature

Nonossifying fibroma (NOF) is a common benign bone neoplasm and is usually observed in the first 2 decades of life. Most NOFs occur in the metaphysis of long bones of the lower extremities and migrate toward the diaphysis during skeletal maturation. Epiphyseal involvement by NOF has been rarely reported, with only one case found in the English literature. The authors report the second case of NOF involving the epiphysis of a long bone, the proximal tibia of a 21-year-old woman. Clinicians and pathologists should be aware of the rare possibility of epiphyseal involvement of long bones by this condition. Pathologists should select appropriate immunohistochemistry markers to rule out alternative diagnoses.

Benign fibrohistiocytic jaw lesions: a 48-year clinicopathologic analysis and review of the literature

OBJECTIVE

Intra-osseous fibrohistiocytic lesions have long been reported in the literature; evidence suggests they represent a heterogeneous group of reactive and neoplastic processes. This study evaluated a series of gnathic fibrohistiocytic lesions to identify and categorize their clinical, radiographic and morphologic spectrum.

STUDY DESIGN

A retrospective case search over 48 years was conducted for maxillary and mandibular intra-bony fibrohistiocytic lesions. Diagnoses were confirmed and demographic, radiographic, clinical and follow-up data was analyzed.

RESULTS

Fifty cases met the inclusion criteria. Most cases (80%) were found in the second through fourth decades (mean, 29 years). The most common location (86%) was the posterior mandible. Radiographic presentations varied, but a few patterns emerged, including a distinctive mottled, honeycomb type with punctate lucencies. All cases demonstrated fibrous components admixed with variable histiocytes. Eight cases (16%) were histiocyte-rich with dominant sheets of xanthoma cells. Immunohistochemical staining revealed strong CD68 and CD163 expression, along with variable smooth muscle actin staining. The vast majority (92%) of cases were treated conservatively. Available follow-up showed lesional stability in 17 cases (average, 85 months) with 2 recurrences (24 months each) and no evidence of malignant transformation.

CONCLUSIONS

This study is the largest to date of fibrohistiocytic gnathic lesions, revealing distinctive radiographic and histologic findings and characteristic clinical and immunophenotypic features. Available evidence suggests that most of these are indolent, slow-growing lesions amenable to conservative therapy.

Benign Fibrous Histiocytoma of Larynx: A Rare Case Report

The Fibrous histiocytoma is one of the mesenchymal tumors that can present as malignant or benign. We reported a 30 years old male, a rare case of benign fibrous histiocytoma of larynx and evaluated the clinical and histological aspect of this patient.

Primary Intraosseous Xanthomas of the Jaws: A Series of Six Cases Including an Example with Formation of Apoptosis-Related Hyaline Globules, So-Called "Thanatosomes"

Primary intraosseous xanthomas of the jaws (PIXJ) are rare and predominantly affect the posterior mandible (86%) of normolipemic patients, with a mean age of 30 years and no gender predilection. Clinically, PIXJ exhibit indolent biologic behavior; curettage is considered treatment of choice. Only 36 PIXJ have been reported. Apoptosis-related hyaline globules (HGs), also known as "thanatosomes", have not been previously reported in PIXJ. Cases diagnosed as xanthoma of bone were retrieved. Six cases fulfilling currently accepted criteria were identified and their clinicopathologic and immunohistochemical properties are presented herein. Mean age for PIXJ was 21.8 years (range = 12-33) and F:M ratio = 2:1. All cases presented as well-demarcated, unilocular or multilocular radiolucencies. Microscopically, PIXJ featured sheets of lipid-laden macrophages with eosinophilic or foamy cytoplasm. A secondary fibroblastic population lacking storiform pattern was evident in two cases. Adipocytes (3/6), peripheral neurovascular bundles (1/6), bone fragments (3/6) and dystrophic calcifications (3/6) were observed enclosed by the xanthoma cells. Notably, one case exhibited numerous, spherical, eosinophilic HGs containing apoptotic nuclei. PIXJ were consistently CD68(+) and negative for CD1α and S100. CD45 decorated lymphocytes and the membrane of foamy histiocytes. Xanthoma cells stained for lysozyme and plasma proteins including alpha-1 antitrypsin (AAT), IgG and IgA in one probed case. HGs were lysozyme(+), AAT(+), IgG(+), IgA(+), PAS(+) and diastase-resistant, and fuchsinophilic with Masson's trichrome. PIXJ represent infrequent, solitary, mandibular lesions with a predilection for the second and third decade of life. Thanatosomes associated with cell injury and death can be present in PIXJ.

Benign Fibrous Histiocytoma of the Talus: A Case Report

Benign fibrous histiocytoma (BFH) is a rare benign primary bone lesion that occurs most frequently in the nonmetaphysis region of the long bones and the pelvic bones. The talus is a rare location for a BFH, which has not been reported previously in the literature. We report the case of a 19-year-old male patient with BFH of the talus, who was treated with curettage, followed by filling of the bone defect with calcium phosphate cement. The patient was free of pain and without local recurrence 5 years after the surgery. We describe the detailed radiographic findings of this rare lesion and discuss the differential diagnosis of such talar lesions.

Arthroscopic Resection for Benign Fibrous Histiocytoma in the Epiphysis of the Femur

A 16-year-old woman presented to her local hospital with a few-month history of right knee pain. On MRI, the lesion exhibited an intermediate signal on T1-weighted and T2-weighted images. The orthopedic physician made a diagnosis of osteochondritis dissecans. After 13 months from the first visit, the patient underwent MRI of the knee once more, which demonstrated that the osteolytic lesion grew larger. To achieve a definitive diagnosis, we attempted to perform a resection biopsy with knee arthroscopy. We performed biopsy, and the tumor was removed completely. The tumor occurred in an epiphysis, and the pathological findings concluded that the pathological diagnosis was benign fibrous histiocytoma. One year after surgery, she was asymptomatic. Computed tomography revealed that the previous tumor bone cavity was filled with bone formation and no evidence of recurrence.

Nonossifying fibroma (metaphyseal fibrous defect) of the mandible in a 15-year-old boy

We describe a rare case of nonossifying fibroma of the mandible in a 15-year-old boy who presented with a left mandibular swelling. Conventional imaging showed an expansile radiolucent lesion involving the angle and the body of the left mandible. The lesion was curetted, and a miniplate was implanted at the excision site. Microscopic examination of the removed specimen revealed a cellular lesion characterized by a proliferation of uniform spindle-shaped cells in a vague but prominent storiform pattern, which represented the classic appearance of nonossifying fibroma. Three months later, radiography detected a fracture of the implantation plate. The area was re-explored with curettage of the soft tissue, which on microscopy demonstrated findings similar to the initial curettage findings. Follow-up radiology revealed satisfactory healing of the jaw, and no further recurrence was seen 2 years after the initial surgery. We present this case to highlight the importance of recognizing nonossifying fibroma in the mandible, which can be easily confused with more common mandibular lesions.

Epithelioid Fibrous Histiocytoma of Bone

A benign fibrohistiocytic neoplasm of bone containing unique epithelioid cells is described in a 54-year-old man who presented with a well-defined lytic lesion in the left calcaneus. Curetted specimens showed microscopic evidence of proliferation of large plump, protoplasmic epithelioid or histiocytic cells with spindled to rounded shape, arranged in a storiform pattern, and osteoclast-like giant cells. This tumor did not show any specific immunoreactivity except for vimentin and actins. In addition to the basic ultrastructural characteristics of fibro/myofibroblasts, the large cells with abundant eosinophilic cytoplasm by light microscopy were shown to be packed with intermediate filaments of the vimentin type. Tumor was treated by curettage and bone grafting and showed radiolucent changes 1 year after operation but had not progressed 3 years later. The term epithelioid fibrous histiocytoma of bone is suggested for this previously undescribed variant of osseous fibrous histiocytoma Int J Surg Pathol 3(1):43-48, 1995

Treatment of intracapsular femoral neck lesions: aggressive or conservative surgery?

Benign fibrous histiocytomas (BFHs) and non-ossifying fibromas (NOFs) are benign bone tumors that are clinically different, but histologically similar. Most benign lesions are treated with curettage and grafting; however, some misdiagnosed cases are treated with more aggressive procedures, including arthroplasty. Herein, we present a 21-year-old patient that presented with a 1-year history of right hip pain. Anteroposterior X-ray showed a centrally located lesion in the femoral neck that was intracapsular and localized subcortically. To the best of our knowledge, the literature does not include any reposts of BFH or NOF localized at the intracapsular hip. In addition, localization of and treatment options for intracapsular hip lesions are clarified.

Non-ossifying fibroma (metaphyseal fibrous defect) of the mandible

A 15-year-old young man was referred for evaluation of a non-tender swelling of the left mandibular angle region. A non-ossifying fibroma was diagnosed. The lesion was enucleated under general anesthesia. The postoperative course was uneventful. There have been no signs of recurrence, and there was complete bone regeneration in the region 24 months after operation. This report also reviews other fifteen cases of non-ossifying fibroma in the mandible reported in the literature.

Benign fibrous histiocytoma arising from the intercostal space

Benign fibrous histiocytoma is a tumor of unknown etiology that is believed to be of mixed fibroblastic and histiocytic origin. Deep benign fibrous histiocytomas are most commonly found in the lower limbs or the head and neck region; it is relatively rare that they are seen in the intercostal space. Only six case reports of this entity are described in the literature. We report a 20-year-old woman who suffered from a painless swelling in the left chest wall, with a computed tomographic correlation. The lesion was totally excised, and histopathology revealed a benign fibrous histiocytoma. This is the first case of a benign fibrous histiocytoma that arose from the intercostal space reported in the English-language literature. The six cases reported in the medical literature are also discussed.

Piezoelectric-assisted removal of a benign fibrous histiocytoma of the mandible: an innovative technique for prevention of dentoalveolar nerve injury

In this article, we present our experience with a piezoelectric-assisted surgical device by resection of a benign fibrous histiocytoma of the mandible.

A 41 year-old male was admitted to our hospital because of slowly progressive right buccal swelling. After further radiographic diagnosis surgical removal of the yellowish-white mass was performed. Histologic analysis showed proliferating histiocytic cells with foamy, granular cytoplasm and no signs of malignancy. The tumor was positive for CD68 and vimentin in immunohistochemical staining. Therefore the tumor was diagnosed as primary benign fibrous histiocytoma. This work provides a new treatment device for benign mandibular tumour disease. By using a novel piezoelectric-assisted cutting device, protection of the dentoalveolar nerve could be achieved.

Oral fibrous histiocytoma and its angiomatoid variant

Fibrous histiocytomas are uncommon mesenchymal tumours of the soft tissue in the head and neck region. We report two cases that occurred in the oral cavity, one of a benign fibrous histiocytoma (BFH) and another of an angiomatoid variant of fibrous histiocytoma (AFH). BFH is a benign neoplasm composed of cells with fibroblastic and histiocytic characteristics, while AFH is considered as a distinct type of fibrous histiocytoma with an intermediate malignancy grade that combines features of both fibrohistiocytic and vascular neoplasm. We describe the clinicopathological and histological characteristics of these lesions to clarify and facilitate their diagnosis. In the BFH case, the surgical specimen had many histiocytes positive for lysozime, whereas the AFH cells showed positivity for endothelial cell marker (anti-CD34 antibody). In both cases the tumours were positive for fibronectin and negative for S100 and SMA. Ki-67. Immunohistochemistry was performed in all cases to reveal the different mitotic activity between AFH and BFH tumour cells. Finally, differential diagnoses and therapeutic treatments are discussed.

Benign fibroxanthoma of the mandible

Histiocytomas constitute a large group of tumors, the classification of which created a lot of confusion in the past. For this reason, various attempts were carried out during the last years so that a widely accepted classification system could be defined. Fibroxanthomas, according to contemporary data, are classified into benign histiocytomas and they are mostly located at the skin of extremities. They are rarely localized in the area of the head and neck, where they are found commonly in soft tissue. Fibroxanthomas located at the bones of oral and maxillofacial region are extremely rare. The purpose of this paper is to present a case of a fibroxanthoma located at the mandible as well as to analyze the histological findings of the lesion on which the diagnosis and differential diagnosis were based.

Benign fibrous histiocytoma of bone in a paediatric population: a report of 6 cases

Case records and radiological investigations of six children with benign fibrous histiocytoma were studied retrospectively. BFH occurred in the femur (n = 2), tibia (n = 2) and fibula (n = 2). Clinically, patients reported pain from the lesion lasting several months (mean 6 months). The pain was not associated with pathological fracture in any patient. On X-rays, the lesions appeared as lytic and sharply demarcated with a sclerotic rim and fine trabeculations. The reported cases were located in the metaphysis and the diaphysis of the long bones. The tumour was restricted to bone, without periosteal or soft tissue reaction. Treatment consisted of careful intralesional curettage of the lesion; the defect was thereafter filled with bone bank graft or injectable phosphocalcic cement. The length of follow-up ranged from 24 months to 4.75 years (mean 35.2 months). One case presented with recurrence of the disease and required successful repeat intralesional curettage. Benign fibrous histiocytoma is probably underestimated among patients less than 20 years of age. This diagnosis should be considered in any child or teenager who presents with a non-ossifying fibroma accompanied by unexplainable pain or a rapid growing. Surgery restricted to the osteolytic lesion seems sufficient to achieve bone healing.

Benign fibrous histocytoma of the distal radius: a report of a case and a review of the literature

Benign fibrous histocytoma of bones is a very rare tumour and only a few cases have been reported. We report a case of 40-year-old patient with no significant previous medical history who presented with a painful lesion in his right wrist joint. Incision biopsy was done and there was a histological picture similar to a metaphyseal fibrous defect (non-ossifying fibroma). This was managed with excision of the lesion and filling the defect with cancellous and cortical bone grafts from the left iliac bone. To our knowledge, this is the second case report of a benign fibrous histocytoma involving the distal radius in adult. In this case report, we review similar cases in the literature and discuss the differential diagnoses of this lesion.

Case report: Fibroxanthoma: a complication of a biodegradable screw

BACKGROUND

Biodegradable interference screws in anterior cruciate ligament (ACL) reconstruction have gained popularity because of their similar or superior fixation strength in comparison to metallic interference screws and because they do not cause imaging artifacts and do not need to be removed.

CASE DESCRIPTION

We report the case of a 23-year-old man who presented with slowly progressive firm swelling of 2 months' duration at the site of the tibial tunnel 3 years after ACL reconstruction using a biodegradable interference screw. After curettage and débridement, the material was sent for histopathologic examination, which was reported as a fibroxanthoma.

LITERATURE REVIEW

Reported complications are osteolysis around the screw, allergic reaction, sterile abscess formation, ganglion cyst formation, and intraarticular migration. A fibroxanthoma consists of fibroblasts and mononuclear or multinucleated cells with large lipid-filled histiocytes (foam cells). The cells are negative for S-100 and keratin and positive for anti-human macrophage marker HAM-56.

PURPOSES AND CLINICAL RELEVANCE

Use of biodegradable screws is associated with high healing rates and low complication rates; however, awareness of their potential complications may help in early recognition and prevention of associated morbidity.

Benign fibrous histiocytoma of the skull with increased intracranial pressure caused by cerebral venous sinus occlusion

The authors present a very rare case of benign fibrous histiocytoma of the skull with increased intracranial pressure caused by sinus occlusion. A 33-year-old woman was referred for investigation of a right occipital protrusion with tenderness and double vision. She had only mild divergence insufficiency and bilateral papilledema neurologically. Imaging findings showed that the skull tumor was located at the right occipital bone with bone disruption and a compressed right sigmoid sinus. When planning the resection, caution was required to spare the collateral flow so as to manage the intracranial pressure. Immunohistochemical analysis showed that the tumor was positive for CD68, α1-antichymotrypsin, and α1-antitrypsin. From these findings, the tumor was diagnosed as a primary benign fibrous histiocytoma of the skull.

Benign fibrous histiocytoma of the hand: a case report and literature review

Benign fibrous histiocytoma (BFH) of the bone is a rare benign lesion characterised by the presence of fibroblasts and histiocytes. Fibrohistocytic lesions involving bone with identical histological appearances are common during childhood such as fibrous cortical defect. However, BFH is very rare and can only be differentially diagnosed with its presentation, localisation and radiologic features. Here we describe a 33-year-old man with BFH in a rare location, a phalanx. To our knowledge this is the second reported case of a BFH involving the proximal phalanx of the thumb in an adult. We report clinical, radiologic and histological findings of the case and briefly review the literature on the subject.

Benign fibrous histiocytoma of the lumbar vertebrae

Benign fibrous histiocytoma is an extremely rare spinal tumor with ten reported cases in the literature. Benign fibrous histiocytoma constitutes a diagnostic challenge because it shares common clinical symptoms, radiological characteristics, and histological features with other benign lesions involving the spine. We present a case of benign fibrous histiocytoma of the lumbar spine and discuss its differential diagnosis and management.

Benign fibrous histiocytoma in the condylar process of the mandible: Case report

A 48-year-old man was referred for investigation of an asymptomatic radiolucent lesion in the mandible. The margin was partly irregular, and there was no peripheral sclerosis. The tumour was composed of histiocytic cells, spindle cells, and fibrous tissue. Immunohistochemical analysis showed that the tumour cells stained for CD68 and vimentin, and not for cytokeratin, smooth muscle actin, S-100 protein, or CD34. The tumour was therefore diagnosed as a benign fibrous histiocytoma.

Benign fibrous histiocytoma of the thoracic spine: case report and review of the literature

Benign fibrous histiocytoma (BFH) is a rare skeletal tumor, accounting for approximately 1% of all surgically managed benign bone tumors. Spinal location is very rare, and its management can be challenging, involving excision of tumor and spinal reconstruction and stabilization. The prognosis is good after treatment. The authors present the case of BFH involving the thoracic spine and a review of the literature concerning BFH of the spine.

Benign fibrous histiocytoma of the sacrum--diagnostic difficulties facing this rare bone tumor

Benign fibrous histiocytoma of bone is rare, and this is the first report of the tumor arising from the sacrum. The descriptive histopathological picture makes the diagnosis more difficult as it resembles many benign and malignant myxoid tumors. In this case report, the diagnostic difficulties involved and a review of the literature in order to describe the optimal management of this condition, have been presented. The clinical presentation of this 18-year-old girl was that of low back ache, radiating along the right posterior leg, of 1 month's duration. On the straight leg raising test, right-sided sciatic nerve compression was detected. Magnetic resonance imaging revealed a large tumor involving and destroying sacral segments S3-S4, homogeneous in intensity and extending into the vertebral canal and the presacral space. There was no enhancement with gadolinium contrast. Core needle biopsy revealed fibrous histiocytoma. Excision through a posterior midline incision was performed taking care to preserve the S1-S2 sacral segments and also the sacral nerves. Additional cauterization with phenol was performed. Postoperatively, the patient had significant improvement in pain with no major residual neurological deficit.

Benign fibrous histiocytoma of the distal radius with congenital dislocation of the radial head: a case report

Benign fibrous histiocytoma is such a rare tumour that only a few cases have been reported in the literature. A patient with an apparently benign lesion of the distal radius, along with congenital dislocation of the radial head, was presented at St. John's Medical College Hospital in Bangalore, India. Pain was the chief symptom. There were histological features of non-ossifying fibroma in the lesion. Because of its unusual radiological appearance and atypical clinical course, the lesion was diagnosed as fibrous histiocytoma. In this case report, we review similar cases in the literature and discuss an unusual association with congenital dislocation of the radial head.

Benign fibrous histiocytoma of the mandible

A very rare case of benign fibrous histiocytoma of the mandible is presented. A 49-year-old woman was admitted because of left buccal swelling and pain. Panoramic radiograph showed well-demarcated soap-bubble appearance without sclerotic rim in the left mandibular bone. A yellowish-white and partly brown solid tumor was noted in the excised mandibular bone specimen. The tumor histologically consisted of spindle cells, in which areas showing a storiform pattern and other areas composed of histiocytic cells with erythrophagocytosis and foam cells were mixed. Immunohistochemically, the tumor cells were positive for vimentin, CD68, alpha-1-antichymotrypsin and alpha-1-antitrypsin. From these findings the tumor was diagnosed as a primary BFH of the mandible. No recurrence has been noted 2 years and 11 months after surgery.

Fibrohistiocitoma benigno ósseo na coluna lombar

CONTEXTO: O fibrohistiocitoma benigno intra-ósseo é uma neoplasia rara, caracterizada por proliferação fibroblástica e fibras colágenas. A dor na região lombar é uma queixa freqüente em muitos pacientes, mas, na maioria das vezes está relacionada com causa muscular ou degenerativa. RELATO DE CASO: Relata-se aqui o caso de um paciente com diagnóstico de fibrohistiocitoma benigno ósseo na coluna lombar que apresentava queixa de lombalgia há cinco meses antes do diagnóstico. Foi submetida à biópsia aberta transpedicular na quarta vértebra lombar ,e, posteriormente realizada curetagem da lesão via anterior retroperitonial e artrodese vertebral de L3-L5 com enxerto de fíbula. CONCLUSÃO: Apesar de raro, o fibrohistiocitoma benigno intra-ósseo deve ser uma das hipóteses quando observamos uma lesão primária na coluna vertebral.

Reconstruction of the pelvic ring using an autologous free non-vascularized fibula graft in a patient with benign fibrous histiocytoma

BACKGROUND

Benign fibrous histiocytomas (BFH) usually presents as a small benign lesion that predominantly occurs in the skin. Only few cases of BFH arising from bone have been reported, its occurrence in pelvic bones is even rarer.

CASE PRESENTATION

A 34-year-old female presented with BFH at a rare anatomical location on both sides of the os ilium which was larger than earlier reported BFH of the bone. Surgical resection was performed successfully including resection of the inner pelvic ring and reconstruction of the linea terminalis using a non-vascularized fibular autograft. At 18 months after tumor resection and reconstruction of the pelvic ring, with interposition of a free vascularized fibula graft patient has an excellent clinical oncological and functional outcome.

CONCLUSION

Non vascularized fibular autograft is a useful reconstructive procedure in select patients.

Benign fibrous histiocytoma in the mandible

PURPOSE

Benign fibrous histiocytoma (BFH) is a very rare benign tumor occurring in the jaw. The purpose of this article is to describe the clinical, radiographic, and microscopic appearance of BFH occurring in the mandible.

STUDY DESIGN

A 42-year-old man had an asymptomatic swelling of the left mandibular posterior area.

RESULTS

Conventional radiographs revealed a well-defined multilocular radiolucency involving the left mandibular body, ramus, coronoid process, and condylar head. The lesion showed the thinning and expansion of the cortex. There were many thin, indistinct septa in the lesion. The computed tomography (CT) scans showed bone destruction with marginal sclerosis and a heterogeneous soft-tissue mass expanding the mandible. Microscopic examination revealed a cellular tumor composed of uniform spindle-shaped cells arranged in a storiform pattern.

CONCLUSIONS

BFH is a very rare benign tumor occurring in the jaw, so more cases should be reported to understand the characteristics of the lesion.

Benign fibrous histiocytoma of the posterior arch of C1 in a 6-year-old boy: a case report

STUDY DESIGN

Presented is a unique case report of a rare bone tumor: a benign fibrous histiocytoma (BFH) located in the posterior arch of C1 in a 6-year-old child.

OBJECTIVE

To describe a benign fibrous histiocytoma of bone and the differential diagnostic considerations based on the authors' case report.

SUMMARY OF BACKGROUND DATA

A BFH is a rare tumor composed of varying degree of fibroblast-like spindle cells, foam cells, and multinucleated giant cells. Approximately 86 cases have been reported in literature. Its exact nature remains somewhat controversial. A lesion may be designated a benign fibrous histiocytoma based on clinical, radiographic, and microscopic criteria.

MATERIALS AND METHODS

The clinical symptoms, plain radiographs, computerized tomography (CT), magnetic resonance images (MRI), bone scintigraphy, and histologic section of the lesion are discussed, evaluated, and compared with other benign bone lesions.

RESULTS

This case is, to the best of the authors' knowledge, the first benign fibrous histiocytoma to be reported in the cervical spine of a child. Various benign lesions such as nonossifying fibroma, giant-cell tumor, fibrous dysplasia, aneurysmal bone cyst, osteoblastoma, and eosinophilic granuloma are included in the differential diagnosis.

CONCLUSION

Benign fibrous histiocytoma is a rare skeletal tumor. Because of this and its nonpathognomonic microscopic features, the diagnosis can be somewhat troublesome. However, by systematically reviewing patient's symptoms, tumor location, and radiographic and microscopic characteristics, other benign lesions can be eliminated. The diagnosis of a BFH is one of exclusion.

Benign fibrous histiocytoma: a rare finding on bone scan staging for prostate adenocarcinoma

Benign fibrous histiocytoma is a rare bone tumor that usually presents with localized pain and/or a pathological fracture. We report on a patient with adenocarcinoma of the prostate who had a radionuclide bone scan for staging, which was suspicious for metastatic disease. Histologic examination of left eleventh rib revealed a Benign Fibrous Histiocytoma (BFH). To our knowledge, this is the first BFH found solely on bone scan.

Benign fibrohistiocytoma (xanthomatous variant) of the acromion. A case report and review of the literature

A number of fibrous lesions involving bone display almost identical histologic appearances yet may represent either reactive or neoplastic conditions, resulting in a confusing nomenclature and possible diagnostic confusion. We report the case of a young man with no significant previous medical history who presented with a painful lesion in the left shoulder, which consisted almost entirely of xanthomatous material. We discuss the possible differential diagnosis of this lesion and why benign fibrous histiocytoma is the preferred terminology for this lesion. To our knowledge, this is the first reported case of a benign fibrous histiocytoma involving the acromion in an adult.

Xanthoma of the temporal bone: case report

OBJECTIVE AND IMPORTANCE

Xanthomas of the cranium that are not accompanied by endocrine or metabolic abnormalities are extremely rare. It is very important to understand the pathological features of this disease, for differential diagnosis from other diseases.

CLINICAL PRESENTATION

A 62-year-old woman presented to the hospital with headaches. Cranial x-rays revealed bone destruction in the right temporal bone, with osteosclerosis in the area surrounding the lesion. In computed tomographic scans, the bone cortex was intact and the diploë was dilated because of the large mass of the lesion. T1-weighted magnetic resonance imaging findings were heterogeneous, with areas of hypo- and isointensity; T2-weighted magnetic resonance imaging findings were also heterogeneous, with areas of hypo- and hyperintensity.

INTERVENTION

Total removal of the tumor was performed, followed by cranioplasty using artificial bone.

DIAGNOSIS

Histologically, lipid-containing foamy cells were dense and a cholesterin granuloma was observed. There was no reason to infer other diseases, and a diagnosis of xanthoma of the temporal bone was reached.

CONCLUSION

Xanthomatous lesions are observed in various pathological conditions, including malignant diseases. Xanthomas are benign lesions and the prognoses for patients with these lesions are satisfactory, even after partial excision. Therefore, it is quite important to distinguish xanthomas from other diseases that produce xanthomatous lesions.

Benign fibrous histiocytoma of the renal capsule

The first case of benign fibrous histiocytoma of the renal capsule is reported in a male aged 44 years. The tumor had its point of origin in the renal capsule. Histologically, the tumor was composed of intersecting fascicles of fibroblastic cells forming a loose crisscross or "storiform" pattern. Electron microscopic studies of tumor cells revealed intermediate filaments and membrane-bound collagen fibers which continued to extracellular collagen bundles. This deep seated fibrous histiocytoma had a more prominent storiform pattern and fewer secondary elements such as xanthoma cells than cutaneous ones.

Benign fibrous histiocytoma involving the ends of long bone

Five bone tumors, previously labelled as benign fibrous histicytoma in our Bone Tumor registry were reviewed. All the cases were reexamined clinically, radiologically, and histologically. Ages of the patients ranged from 17 to 68 years and all tumors involved the epiphysis or epiphysiometaphysis of long tubular bones. A diagnosis of giant cell tumor was suggested from initial radiographs in all cases. Three cases proved to be giant cell tumors of bone after thorough examination of previous histological specimens. In the diagnosis of benign fibrous histocytoma of epiphyseal origin in adults, the possibility of giant cell tumor of bone should always be kept in mind, and painstaking histological examination is required.

Benign fibrous histiocytoma of the maxilla

Benign fibrous histiocytomas of bone are unusual neoplasms that often are confused with metaphyseal fibrous defects. Although the two lesions have overlapping microscopic characteristics, they differ in their clinicopathologic presentations. This report describes the clinicopathologic features of the first reported case of benign fibrous histiocytoma involving the maxilla and the fourth description of this tumor in the jawbones. In addition, the concept of fibrohistiocytic lesions of bone is discussed with consideration of their pathologic classification and their clinical, radiographic, and microscopic differential diagnosis.

Aneurysmal bone cyst. A review of 123 cases including primary lesions and those secondary to other bone pathology

A group of 639 bone lesions was reviewed in order to study the features of the aneurysmal bone cyst and its association with other conditions. A diagnosis of primary aneurysmal bone cyst not associated with any other bone lesion was made in 87 patients. In 36 additional patients the gross and microscopic changes of aneurysmal bone cyst were identified as part of some other solid bone lesion. Fourteen of these additional cases were associated with giant cell tumor (96 cases studied), six with chondroblastoma (41 cases studied), three with chondromyxoid fibroma (45 cases studied), two with nonossifying fibroma (68 cases studied), four with osteoblastoma (61 cases studied), one with fibrosarcoma (50 cases studied), three with fibrous histiocytoma (45 cases studied), two with osteosarcoma (100 cases studied), and one with fibrous dysplasia (42 cases studied). The age, site, and sex distribution of the cases associated with another lesion compares closely with that of the solid lesion concerned, supporting the concept that the aneurysmal bone cyst component is secondary.