Metaplastic Bone Formation Research Articles

Dedifferentiated liposarcoma with peculiar meningothelial-like whorling and metaplastic bone formation, case report

Dedifferentiated liposarcoma represents a both morphologically and biologically fascinating lesion in which transition from low-grade to high-grade nonlipogenic morphology within a well-differentiated liposarcoma is observed. A peculiar form of dedifferentiated liposarcoma characterized by a nonlipogenic component with a meningothelial- like whorling pattern of growth and metaplastic bone formation has been described. A 59-year-old man presented with a pelvic retroperitoneal mass measuring 13x10x8 cm. Histopathologically the mass consisted almost entirely of a dedifferentiated nonlipogenic component with meningothelial-like whorling pattern, metaplastic cartilage and bone. Dedifferentiated liposarcoma with meningothelial- like whorling pattern has rarely been encountered. Here, we report this case because of the problems in differential diagnosis especially for cases that have an extensive dedifferentiated component and the uncertainty of the biological behavior of these tumors.

Isolated calcified amyloidoma of the abdominal wall mimicking sarcoma

Amyloidoma is a localized tumoral deposition of amyloid protein without systemic involvement. Though rare, it has been reported in various tissues. Calcified amyloidoma is an extremely uncommon condition that can mimic benign and malignant soft tissue tumors. Here, we report a case of isolated calcified amyloidoma, which clinically simulated a soft tissue sarcoma. A 60-year-old previously healthy female presented with a slow growing hard mass in her left lower abdomen. She denied any pain, weight loss, B symptoms, history of surgery or significant trauma. Imaging studies confirmed the presence of a heterogeneous mass within the abdominal muscles. With the clinical suspicion of sarcoma, a core biopsy was obtained which showed focal necrosis and granulomatous reaction. The mass was surgically excised. Histopathological evaluation revealed the concentric deposition of dense amorphous eosinophilic material associated with metaplastic bone formation, lymphoplasmacytic infiltrate and multinucleated giant cells. The eosinophilic deposit showed strong reactivity with Congo red stain and displayed typical apple-green birefringence under polarized light confirming amyloid. Normal serum protein electrophoresis and hematological studies ruled out an underlying systemic plasma cell dyscrasia. Primary localized amyloidoma should be considered in the differential diagnosis of soft tissue masses even in the absence of systemic amyloid disease.

Chromophobe renal cell carcinoma with concomitant sarcomatoid transformation and osseous metaplasia: a case report

BackgroundChromophobe renal cell carcinoma is the third most common form of adult renal epithelial neoplasm. A sarcomatoid component occurs in approximately 8% of all chromophobe renal cell carcinoma cases, while metaplastic bone formation is extremely rare.Case presentationAn abdominal computed tomography scan revealed a hypovascular tumor with focal calcification, measuring 2.5 × 2.3 cm, in the upper pole of the right kidney. The tumor was clinically diagnosed as a right renal cell carcinoma that showed signs of calcification, and a laparoscopic right radical nephrectomy was performed. The cut surface of the tumor was beige in color and indicated that the tumor was an extensively ossified mass. Histological analysis revealed three distinct morphological components of the tumor. The chromophobe renal cell carcinoma consisted of compact epithelial cells arranged in a nested pattern, and these were mixed with extensive areas of sarcomatoid spindle cells with marked nuclear pleomorphism and brisk mitotic activity. The tumor also contained multiple foci of metaplastic ossification.ConclusionChromophobe renal cell carcinoma with concomitant osseous metaplasia and sarcomatoid transformation is a very rare occurrence.

Metaplastic Bone Formation in the Abdominal Wall—An Incidental Finding in a Patient With Gastric Cancer. Case Report and Hypothesis About Its Histogenesis

A 64-year-old man was hospitalized showing symptoms suggesting gastric cancer. The gastroscopy showed a 70 × 30-mm tumor. The intraoperatory findings indicated an inoperable gastric tumor located in the antrum and gastric body, which invaded the spleen and pancreas. The abdominal incision was closed without performing gastrectomy. Considering his general condition, after 1 month, he was transferred to our hospital. We decided to perform a total gastrectomy of necessity, spleno-pancreatectomy, and dissection of regional lymph nodes. The surgical incision was performed along to the previous one. At palpation, a well-defined nodule with hard consistency was observed in the surgical scar, which microscopically was composed by osteoblasts-lining mature lamellar bone intermingled with osteoid and cartilage in the intermediary layer and fibroblasts in the central area, without atypia. The final diagnosis was localized metaplastic bone formation. This is a rare condition which can be related to trauma or surgery and should be differentiated by foreign-body granuloma and osteosarcoma.

RENAL CELL CARCINOMA WITH OSSEOUS METAPLASIA OCCURRING IN A CONTRACTED KIDNEY - A RARE CASE REPORT

AbstractOsseous metaplasia is a rare histologic feature associated with renal cell carcinoma, occurring in a contracted kidney is still rarer. Metaplastic bone formation within the renal tumor gives an appearance similar to that of calcification. It is difficult to distinguish between bone formation and calcification on the basis of radiological imaging alone. Prognostic significance of metaplastic bone formation in renal cell carcinoma is not clear, however some report suggest good prognosis as a result of limitation of tumor spread by bone formation. This case report highlights the occurrence of renal cell carcinoma with osseous metaplasia in a contracted kidney.

Survival of diced and block cartilage grafts in combination with injectable calcium hydroxylapatite

Dorsal nasal irregularities after trauma, and various procedures such as excessive nasal hump resection, are major problems for patients who have undergone rhinoplasty. Many grafts have been described for the correction of dorsal nasal irregularities. In this study, we used an injectable implant, in combination with diced or block cartilage grafts, to test the efficacy of injectable calcium hydroxylapatite on the survival of diced or block cartilage grafts. Prospective, controlled, parallel group animal study. Fourteen New Zealand white rabbits were used. Block cartilage and diced cartilage grafts, alone and in combination with injectable calcium hydroxylapatite, were placed subcutaneously in the rabbits' dorsal thoracolumbar region. On the 90th day following surgery, the graft areas were extracted immediately after the rabbits were sacrificed. Pathological examination was conducted on all specimens. The pathologic and histochemical findings were compared between groups. There was chronic inflammation observed in all of the groups. However, none of the groups had metaplastic bone formation or calcification. The group that received diced cartilage in combination with the injectable implant received the highest scores for peripheral chondrocyte proliferation, matrix collagen, elastic fiber, and proteoglycan content (P < 0.05). A comparison of the block and diced cartilage grafts revealed that peripheral chondrocyte proliferation was more pronounced in the diced cartilage grafts (P < 0.05). The use of calcium hydroxylapatite in combination with diced cartilage grafts does not have any long-term negative effects on chondrocyte viability.

EWSR1-CREB3L1 Gene Fusion

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon sarcoma with a deceptively bland-looking morphology that disguises its malignant clinical behavior. It shows distinctive chromosomal translocations resulting in fusion of FUS with the CREB3L2 gene in most cases and CREB3L1 in rare cases. Thus molecular studies are particularly helpful in the diagnosis of this bland-looking sarcoma. We report 2 cases of LGFMS serendipitously found to harbor a novel alternative EWSR1-CREB3L1 gene fusion, as confirmed by DNA sequencing of reverse transcriptase-polymerase chain reaction products and fluorescence in situ hybridization. One patient was a child who presented with a subcutaneous nodule on the lower leg, and the other was a middle-aged woman who had a mass lesion over the proximal thigh. Morphologically, one case showed a spindle cell tumor with hyalinization and giant rosettes, whereas the other showed classical histology of LGFMS with focal metaplastic bone formation. Immunostaining for MUC4 showed extensive positive staining. Our findings therefore expand the spectrum of gene fusions that characterize LGFMS and suggest that the EWSR1 gene may substitute for the function of FUS in gene fusions of sarcoma.

Lung ossification: an orphan disease.

Diffuse pulmonary ossification (DPO) is a rare entity which is characterized by metaplastic bone formation in the lung parenchyma. It is an uncommon condition without significant symptoms, which is usually diagnosed on autopsy. Diffuse pulmonary ossification can be easily misdiagnosed as one of interstitial lung diseases due to diffuse pulmonary lesions. Two types of diffuse ossification are described in medicine: dendriform and nodular. In this article, the authors present a patient with persistent pneumothorax who underwent investigation of the cause of his disease and a diagnosis of DPO was revealed.

Dystrophic Cutaneous Calcification and Metaplastic Bone Formation due to Long Term Bisphosphonate Use in Breast Cancer

Bisphosphonates are widely used in the treatment of breast cancer with bone metastases. We report a case of a female with breast cancer presented with a rash around a previous mastectomy site and a discharge lesion on her right chest wall in August 2010. Biopsy of the lesion showed dystrophic calcification and metaplastic bone formation. The patient's history revealed a long term use of zoledronic acid for the treatment of breast cancer with bone metastasis. We stopped the treatment since we believed that the cutaneous dystrophic calcification could be associated with her long term bisphosphonate therapy. Adverse cutaneous events with bisphosphonates are very rare, and dystrophic calcification has not been reported previously. The dystrophic calcification and metaplastic bone formation in this patient are thought to be due to long term bisphosphonate usage.

Desmoplastic ameloblastoma with osteoplasia: Review of literature with a case report

Desmoplastic ameloblastoma (DA) is a relatively rare histological variant of ameloblastoma with specific clinical, radiological, and histological features. This tumor is more commonly seen in the anterior region of jaws as a mixed radiopaque-radiolucent lesion resembling benign fibro-osseous lesions. Histologically, DA is characterized by small nests and strands of “compressed” odontogenic epithelium supported by pronounced collagenized stroma. Metaplastic bone formation has been reported in few cases. This report describes a lesion in the left anterior maxilla of a young female patient.

Medial Humeral Epicondylitis in Cats

To describe medial humeral epicondylitis in cats based on radiographic, anatomic, and histologic observations. Prospective cohort study. Feline cadavers (n = 60). Extended craniocaudal, and extended and flexed mediolateral radiographic projections were taken of both elbows of 60 consecutive European shorthair cats that died or were euthanatized. Elbows with new bone formation at the medial epicondyle were dissected and embedded in methyl-methacrylate (MMA). For comparison, both elbows of a cat with no radiographic changes were prepared in a similar manner. Sections of the MMA blocks were Giemsa stained and examined with light microscopy. Bilateral new bone formation was identified radiographically at the medial aspect of the humeral epicondyle in 6 cats (10%). All of these cats had mineral deposition in the humeral head of the flexor carpi ulnaris muscle. Other findings were cartilage damage (n = 3 cats), an additional loose medial joint body (1), and tendinosis (3). The ulnar nerve was flattened and displaced caudally, and signs of chronic epineural fibrosis were present in 2 severely affected cats. Ten percent of this feline population had radiographic evidence of medial humeral epicondylitis with chronic degeneration, mineralization, and metaplastic bone formation in damaged fibrillar matrix involving the origin of the humeral head of the flexor carpi ulnaris muscle. New bone formation caused displacement and compression of the ulnar nerve in severely affected elbows. Based on our findings, medial humeral epicondylitis appears to be a common disorder in cats with potential clinical sequelae.

Giant Suprasellar Rathke's Cleft Cyst Mimicking Craniopharyngioma: Implications for a Spectrum of Cystic Epithelial Lesions of Ectodermal Origin

Cystic epithelial lesions such as Rathke's cleft cysts (RCCs) and craniopharyngiomas may be difficult to distinguish on a clinical, radiographic, and sometimes histopathological basis. We describe a case of a giant 6.5 cm suprasellar cystic lesion that was presumed to be a craniopharyngioma based on the neuroimaging findings. The lesion extended from the anterior skull base and sella turcica to the lateral ventricle and sylvian fissure resulting in obstructive hydrocephalus. Complete surgical removal of the suprasellar lesion was achieved using an extended frontotemporal transbasal skull base approach. Intraoperatively, the cyst wall was thickened and partially calcified, resembling a craniopharyngioma. However, the histopathological examination revealed findings most consistent with a RCC with additional features of extensive squamous metaplasia, metaplastic bone formation, and chronic inflammation. The case raises the issue of whether there is a pathologic continuum of parasellar ectodermal lesions which may account for the overlap of features and transitional states. In this report, we discuss the possible spectrum between RCCs and craniopharyngiomas, and also emphasize the importance of complete resection of the cyst wall in RCCs that exhibit squamous metaplasia, inflammation, or ossification to minimize the probability of recurrence.

Ectopic bone formation in a subsegmental bronchus

A 48-year-old man with fever and dry cough was admitted to our hospital. Imaging examinations revealed a mass lesion with calcification in the right B(3)b bronchus and atelectasis in the distal lung area. Subsequently, right S(3) segmentectomy was performed. There was a hard polypoid mass completely obstructing the right B(3)b bronchus. Histopathological findings suggested a metaplastic bone formation with mature bone marrow tissue leading to the primary bronchial cartilage. A case of ectopic bone formation in subsegmental bronchus has never been reported thus far. The resident fibroblasts might transform into osteoblasts under appropriate environmental conditions and induce bone formation.

Critical histopathological analysis of 25 dedifferentiated liposarcomas, including uncommon variants, reviewed at a Tertiary Cancer Referral Center

De-differentiated liposarcomas (DDLSs) are uncommon tumors with a wide histopathological spectrum. Over an 8-year period (2003-2011), 25 DDLSs, after review, were critically analyzed for histopathological features. Twenty-five tumors, in 14 men and 11 women (M: F = 1.2:1), with age range of 22-88 years (mean, 53.9), occurred in retroperitoneum (14) (56%), thigh (3) (12%), paratesticular region (3) (12%), chest wall (2) (8%), leg (1) (4%), shoulder (1) (4%), and groin (1) (4%). Tumor size (21 tumors) varied from 7.5 to 25 cm (mean, 17.5). Histopathologically, DD component was high grade in 19 (76%) and low grade in 6 (24%) tumors. Whereas the most common WD component was adipocytic type; the most common DD component was pleomorphic sarcomatous (13) (52%), followed by myxofibrosarcomatous (MFS)-type (6) (24%). Low-grade DD components included MFS (2), fibrosarcoma (2), myogenic/myofibroblastic type (1), and IMFT-type (1). Three tumors displayed meningothelial-like whorls and metaplastic bone formation. Heterologous elements, noted in 11 (44%) tumors, included bone (8) and rhabdomyoblastic differentiation (2). Two tumors displayed homologous differentiation, reinforced with MDM2 staining. S100-P was diffusely positive in WD components (5/7) and focally in DD components (2/9). All patients were treated with surgery, including 10, who underwent adjuvant radiotherapy. Outcomes (16 patients, 64%), over 1-48 months included 10 patients free of disease, 4 died of disease, and 2 patients alive with disease. This study forms the largest documentation of DDLSs, including its wide histopathological spectrum, from our country. Rare cases overlap with pleomorphic liposarcoma. S100-P and MDM2 are useful in substantiating adipocytic differentiation, especially in selected cases. Analysis of adequate tumor sections is vital for correct identification of a DDLS. Surgical excision with adjuvant RT forms optimal treatment.

Atypical lipomatous tumor with unusual extensive metaplastic ossification

The presence of metaplastic ossification within atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) is a rare occurrence. When present, bone formation is most often found in association with a dedifferentiated component arising within the primary tumor. It is important for the radiologist not only to recognize the differential diagnosis of a calcified or ossified soft tissue mass but also be aware of the various soft tissue neoplasms, both aggressive and non-aggressive, that may show such features. We report a case of ALT/WDLPS with unusual extensive metaplastic bone formation without an element of dedifferentiated liposarcoma.

Intracerebral metaplastic meningioma with prominent ossification and extensive calcification

We present a patient (male 26 years) with a short history of recurrent seizures induced by a largely intracerebrally located frontal lobe meningioma. The tumor displayed a heretofore unpublished combination of extensive metaplastic bone formation and prominent non-psammomatous calcifications with focal chicken-wire pattern.

The viability of diced cartilage grafts wrapped in autogenous fascia and AlloDerm ® in a rabbit model

Diced cartilage grafting has re-emerged as a popular method in aesthetic rhinoplasty since the introduction of Erol's Turkish delight technique. However, an extensive literature review indicates that diced cartilage grafts with Surgicel(®) wrapping are usually absorbed and often fail to correct associated clinical problems. Recent studies show that significant foreign-body reactions occur in diced cartilage grafts wrapped in Surgicel(®), but not in grafts wrapped in fascia. However, to date, no study has addressed the histological behaviour of diced cartilage wrapped using AlloDerm(®). The primary aim of this study was to compare the viability of diced cartilage wrapped in autogenous fascia to diced cartilage wrapped in AlloDerm(®) in a rabbit model. Ear cartilage and lumbosacral fascia were obtained from six New Zealand white rabbits. Diced cartilage grafts were transplanted to three surgically created subcutaneous pockets on the backs of the rabbits. The rabbits were divided into control group and two experimental groups: control group (group I): diced cartilage (n = 6); experimental group I (group II): diced cartilage wrapped in fascia (n = 6); and experimental group II (group III): diced cartilage wrapped in AlloDerm(®) (n = 6). The grafts were observed 6 months after implantation. Histological processing of the specimens included haematoxylin-eosin (H&E), Masson trichrome, safranin-O, Van Gieson and immunohistochemical staining for glial fibrillary acidic protein. Statistical analysis was performed using the Mann-Whitney test. Results were evaluated at a p < 0.05 significance level. Our histological analysis demonstrated that the chondrocyte regeneration potential, matrix collagen content, and metaplastic bone formation of the AlloDerm(®)-treated group were significantly superior to those of the fascia-treated group. With respect to other histological parameters, the AlloDerm(®)-treated group showed better results than the fascia-treated group, but these results were not statistically significant. The results of our experimental study suggest that AlloDerm(®) may be an excellent material for diced cartilage grafting. Further studies are needed to evaluate the clinical applications of AlloDerm(®) in diced cartilage grafting.

Dedifferentiated Liposarcoma With Meningothelial-like Whorls, Metaplastic Bone Formation, and CDK4, MDM2, and p16 Expression

We studied 5 cases of dedifferentiated liposarcoma with meningothelial-like whorls and metaplastic bone formation, assessing morphology and immunohistochemical expression of a panel of antigens (CDK4, MDM2, and p16 proteins, desmin, smooth muscle actin, h-caldesmon, CD34, AE1/AE3, epithelial membrane antigen, claudin-1, S100 protein, CD21, CD35, CD117, β-catenin, vimentin, and MIB1). The specimens were from the retroperitoneum (3), pelvis (1) or paratesticular region (1), and all 5 specimens comprised exclusively or predominantly dedifferentiated liposarcoma. All 5 dedifferentiated liposarcomas showed prominent metaplastic bone, 3 produced cartilage, and 1 also had osteosarcomatous tissue. The whorls comprised concentric distributions of spindle or epithelioid cells. All cases expressed smooth muscle actin, 3 strongly, whereas 4 cases showed at least focal claudin-1 positivity. In all cases, the whorls expressed at least 2 of CDK4, MDM2, and p16. The presence of 2 morphologic subsets and the immunohistochemical findings suggest that the whorls in these dedifferentiated liposarcomas exhibit divergent myofibroblastic and possibly perineurial differentiation. The CDK4, MDM2, and p16 expression in the whorls suggests that they share a similar genetic background to well-differentiated and dedifferentiated liposarcoma, and that additional genetic events are causal to their distinct morphology.

Gastric carcinoma with osteoclast-like giant cells. Lymphoepithelioma-like carcinoma with Epstein-Barr virus infection is the predominant type

Osteoclast-like giant cells (OGC) are rare in gastric carcinomas. Histopathological study of seven gastric carcinomas with OGC demonstrated three distinct types: lymphoepithelioma-like carcinoma (LELC), non-LELC, and giant cell tumor (GCT) types. LELC is a poorly differentiated adenocarcinoma with prominent lymphoid stroma. The LELC type (n = 4) showed similar histology to LELC of the stomach, except that they were accompanied by OGC and granulomatous reaction. Epstein-Barr virus (EBV) infection was demonstrated by EBV-encoded RNA (EBER) in situ hybridization (ISH) in all the neoplastic cells. The non-LELC type (n = 2) consisted of EBV-negative carcinoma cells with inflammatory infiltrates. OGC and granulomas were frequently observed in the glandular lumens with accumulated mucus. The GCT type (n = 1) was a neuroendocrine carcinoma, containing many OGC with metaplastic bone formation, which showed typical morphological features of OGC in GCT of the bone. In all three types, OGC expressed CD68, but not cytokeratin, indicating that OGC had a reactive histiocytic lineage. Both LELC and non-LELC types are included in the differential diagnosis of isolated granulomatous gastritis, and EBER-ISH was useful for the identification of LELC type. Both LELC and no-LELC types were also suggested to have better prognoses, but the behavior of the GCT type needs to be further characterized.

Metaplastic Bone Formation in the Orbit

Osseous or cartilaginous metaplasia in the orbit are both rare phenomena. The authors describe a unique case of combined primary orbital osseous and cartilaginous metaplasia presenting with orbital pain and ocular dysmotility and discuss the radiologic, histopathologic, and clinical features. This entity should be considered in the differential diagnosis of an orbital mass showing similar radiographic features of calcification.