Fibromyxoid Tumor Of Soft Parts Research Articles

Ossifying Fibromyxoid tumor of soft parts in head and neck: case report and literature review

BackgroundOssifying fibromyxoid tumor of soft parts (OFMT), is a rare but morphologically distinctive neoplasm of uncertain histogenesis that most frequently affects middle-aged male adults. Clinically, it usually presents as a slowly enlarging, small, circumscribed mass, which in most cases is painless. OFMT is most frequently found within the subcutaneous tissues of extremities or trunk, and rarely in the oral/head and neck region. We present an unusual case of this tumor in the submandibular region, and, based on the current medical literatures this is probably the first case described in this anatomical location.Case presentationA 32-year-old male presented to our outpatient clinic with a right submandibular mass with 1-year of evolution. Excisional biopsy showed that it was characterized by ossification along the periphery of the lesion. The neoplastic cells were spindle-like with scant eosinophilic cytoplasm. These cells were arranged with uniform cell-to-cell space in a fibromyxoid stroma. Small and large clusters of calcifications were present within the tumor. Immunohistochemically, the case showed positive staining of S-100 protein, vimentin, nestin, calponin, SMA, GFAF, desmin, INI-1, caldesmon, and CD34. It also showed negative staining of CK, CK7, CK8/18, NF, and EMA. About 2% of neoplastic cells showed positive staining of Ki67. Based on these features, the final pathological diagnosis was OFMT.ConclusionsIt is hoped that a greater understanding of OFMT in the head and neck region will avoid potential misdiagnosis, and contribute to determining the correct management, which appears to be complete surgical excision with close follow-up for recurrence surveillance.

PHF1 Rearrangements in Ossifying Fibromyxoid Tumors of Soft Parts

Ossifying fibromyxoid tumor of soft parts (OFMT) is a rare soft tissue neoplasm of uncertain differentiation. Very recently recurrent rearrangements of the PHF1 gene have been reported in OFMT, including typical, atypical, and malignant variants. We sought to validate and extend these findings in a larger series of well-characterized OFMT, in particular malignant variants. Slides and blocks from 41 OFMT were retrieved, rereviewed, and classified as typical, atypical, and malignant using previously published criteria. Interphase fluorescence in situ hybridization (FISH) was performed on paraffin-embedded sections of each case using a break-apart probe strategy, with direct-labeled FISH probes designed from bacterial artificial chromosomes. The 41 tumors occurred in 23 men and 18 women with a mean age of 55 years and involved the head and neck, trunk, and upper and lower limbs. The tumors were classified as typical (n=14), atypical (n=6) and malignant (n=21). PHF1 rearrangements were detected in 20 of 41 cases (49%) including 43% typical, 50% atypical, and 52% malignant cases. The results of our study confirm previous findings, with PHF1 rearrangements present in nearly 50% of OFMT, including roughly similar percentages of typical, atypical, and malignant tumors. These results support our previous hypothesis that OFMT might represent a translocation-associated tumor, underscore the likely importance of PHF1 rearrangements in the pathogenesis of these lesions, confirm the relationship between typical and malignant OFMT, and suggest a role for PHF1 FISH in the diagnosis of morphologically challenging cases.

Recurrent Rearrangement of the PHF1 Gene in Ossifying Fibromyxoid Tumors

Ossifying fibromyxoid tumor (OFMT) is a soft tissue tumor of unknown lineage. Although most cases are histologically and clinically benign, some show malignant morphological features and local recurrences are not uncommon; a few may even metastasize. In the present study, cytogenetic analysis identified different structural rearrangements of chromosome band 6p21 in tumor cells from three cases of OFMT, including one with typical, one with atypical, and one with malignant morphological features. Mapping of the 6p21 breakpoint by fluorescence in situ hybridization (FISH) indicated that the PHF1 gene was rearranged in all three cases. Further FISH, 5'-rapid amplification of cDNA ends, and RT-PCR analyses disclosed an EP400/PHF1 fusion transcript in one of the cases. Interphase FISH on tumor sections from 13 additional cases of OFMT showed rearrangement of the PHF1 locus in four of four typical, two of three atypical, and one of six malignant lesions. Thus, the PHF1 gene, previously shown to be the 3'-partner of fusion genes in endometrial stromal tumors, is also recurrently involved in the pathogenesis of OFMTs, irrespective of whether they are diagnosed as typical, atypical, or malignant lesions. The PHF1 protein interacts with the polycomb-repressive complex 2 (PRC2), which, in turn, regulates the expression of a variety of developmental genes. Thus, the results indicate that deregulation of PRC2 target genes is crucial for OFMT development.

Cytological features of ossifying fibromyxoid tumor of soft parts

A case of ossifying fibromyxoid tumor (OFMT) evaluated during an intraoperative pathological consultation is presented. The patient, a 70-year-old woman was being followed because of a tumor in the left buttock. Cytological smears were obtained after scrapping the tumoral cut surface and revealed a myxoid background with fragments composed of a denser, fibrillar metachromatic stroma with accompanying round to oval tumoral nuclei and no vessels. Single cells were predominantly monomorphic with a round to oval morphology and scarce cytoplasm. The most relevant feature of the tumor was its peripheral, plaque-like, calcified consistency. The review of the cytological descriptions of four cases revealed similar findings that can be presumed as those of a low-grade myxoid tumor of round to oval cells. A specific recognition of OFMT based solely on cytological features seems difficult. However, when such features are coupled with characteristic radiological findings (peripheral calcification) this entity must be considered.

Ossifying Fibromyxoid Tumor of Soft Parts

Ossifying fibromyxoid tumor (OFMTs) of soft parts is a rare soft tissue and bone tumor of borderline malignancy displaying an uncertain line of differentiation. The existence of fully malignant OFMT is controversial. To better understand the natural history and line of differentiation taken by OFMT, we studied 46 cases by light microscopic, immunohistochemical (IHC), genomic, proteomic, and fluorescence in situ hybridization (FISH) methods. Cases were classified according to the 2003 Folpe and Weiss system. Clinical and follow-up information was obtained. IHC for S-100 protein, desmin, epithelial membrane antigen (EMA), cytokeratins, smooth muscle actin (SMA), INI-1, neurofilament protein (NFP), CD56d excitatory amino acid transporter-4 (EAAT4), and MUC4 was performed on formalin-fixed, paraffin-embedded (FFPE) tissues. Gene expression profiling and proteomic studies were conducted on FFPE tissues from 13 and 5 cases, respectively. FISH for INI-1 was performed on 10 cases. The 46 tumors arose in 29 men and 17 women (median age, 52 y; range 39 to 63 y) and involved the proximal (N=17) and distal extremities (N=13), head and neck (N=9), and trunk (N=5). Median tumor size was 5.4 cm (range, 1.0 to 21.0 cm). Cases were classified as typical OFMT (26 of 46, 57%), atypical OFMT (5 of 46, 11%), and malignant OFMT (15 of 46 cases, 32%). Clinical follow-up (27 cases, median 55 months' duration) showed all patients with typical and atypical OFMT to be alive without disease. Adverse events, including 3 local recurrences, 3 metastases, and 3 deaths, were seen only in malignant OFMT. IHC results were as follows: S-100 protein (30 of 41, 73%), desmin (15 of 39, 38%), cytokeratin (4 of 35, 11%), EMA (5 of 32, 16%), SMA (2 of 34, 6%), INI-1 (lost in mosaic pattern in 14 of 19, 74%), EAAT4 (31 of 39, 80%), MUC4 (3 of 14, 21%), NFP (8 of 10, 80%) and CD56 (6 of 14, 43%). Gene expression profiling showed typical and malignant OFMTs to cluster together, distinct from schwannian tumors. Proteomic study showed expression of various collagens, S-100 protein, and neuron-related proteins. FISH showed INI-1 deletion in 5 of 7 (71%) cases. We conclude that malignant OFMTs exist and may be recognized by the previously proposed criteria of Folpe and Weiss. Expression of neuron-related markers, in addition to Schwann cell and cartilage-associated markers, suggests a "scrambled" phenotype in OFMTs. Loss of INI-1 or other genes on 22q is likely important in the pathogenesis of these rare tumors.

Ossifying fibromyxoid tumour of soft parts: report of a case diagnosed on fine needle aspiration cytology

Ossifying fibromyxoid tumour of soft parts: report of a case diagnosed on fine needle aspiration cytology

Ossifying fibromyxoid tumor of soft parts mimicking a schwannoma with uncommon histology: a potential diagnostic pitfall

Journal of Cutaneous PathologyVolume 36, Issue 1 p. 71-73 Ossifying fibromyxoid tumor of soft parts mimicking a schwannoma with uncommon histology: a potential diagnostic pitfall Miguel Martinez-Rodriguez, Miguel Martinez-Rodriguez Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorManish Mani Subramaniam, Manish Mani Subramaniam Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorAna Maria Calatayud, Ana Maria Calatayud Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorDavid Ramos, David Ramos Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorSamuel Navarro, Samuel Navarro Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorAntonio Llombart-Bosch, Antonio Llombart-Bosch Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this author Miguel Martinez-Rodriguez, Miguel Martinez-Rodriguez Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorManish Mani Subramaniam, Manish Mani Subramaniam Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorAna Maria Calatayud, Ana Maria Calatayud Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorDavid Ramos, David Ramos Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorSamuel Navarro, Samuel Navarro Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this authorAntonio Llombart-Bosch, Antonio Llombart-Bosch Department of Pathology, University Hospital of Valencia, Valencia, Spaine-mail: mimarro111@hotmail.comSearch for more papers by this author First published: 31 December 2008 https://doi.org/10.1111/j.1600-0560.2007.00976.xCitations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume36, Issue1January 2009Pages 71-73 RelatedInformation

Ossifying Fibromyxoid Tumor of Soft Parts—A Clinicopathologic and Immunohistochemical Study of 104 Cases With Long-term Follow-up and a Critical Review of the Literature

Ossifying fibromyxoid tumor (OFT) is a unique soft tissue tumor of uncertain histogenesis. The majority of reported cases (approximately 220) have pursued a benign clinical course. However, recent literature has emphasized the existence of morphologically atypical and clinically malignant examples of this tumor and proposed guidelines for assessment of biologic potential. In the present study, we evaluated 104 cases of OFT from the Armed Forces Institute of Pathology, accessioned between the years 1970 and 2007. Herein, OFT was strictly defined as a tumor with lobular architecture, predominantly epithelioid cell morphology, a low level of atypia, corded and trabecular growth patterns, moderate amounts of myxocollagenous matrix, and often, focal peripheral metaplastic bone formation. Tumors that lacked conventional morphology were excluded. The exclusion group included cutaneous mixed tumors, low-grade fibromyxoid sarcomas, and extraskeletal osteosarcomas. The OFTs occurred in 64 men and 40 women with a median age of 50 years (range, 21 to 81 y). The tumor size ranged from 0.7 to 17 cm (median, 3 cm). The mitotic rate varied from 0 to 41 mitotic figures per 50 HPFs (median, 2/50 HPFs). Tumor cell nuclei typically contained small, distinct nucleoli, and necrosis was infrequent (11/104). The great majority of tumors (67/71, 94%) were positive for S100 protein, whereas only occasional examples had (focal) positivity for desmin, glial fibrillary acidic protein, and an AE1/AE3 keratin cocktail. Local recurrences were documented in 9 of 41(22%) living patients, usually 10 or more years after primary surgery, but there were no metastases. A mitotic rate of >2 mitotic figures/50 HPFs was a risk factor for local recurrence, but necrosis, tumor size, the presence of satellite nodules, and positive margins were not. When OFT is strictly defined by the criteria noted above, there is potential for local recurrence, but there seems to be little or no risk for metastasis.

Ossifying fibromyxoid tumor of soft parts with clonal chromosomal aberrations

Ossifying fibromyxoid tumor (OFMT) is a rare but morphologically distinctive soft-tissue tumor. The histologic origin of this tumor is not clearly known, but its various features suggest a schwannian, neuronal, or chondroid origin. We herein report a case of a typical OFMT that occurred in the shoulder of a 65-year-old man. The karyotype exhibited the following complex numeric and structural aberrations: 42∼46,XY,-Y,add(1)(q42),add(6)(p21),t(10;18)(q26;q11),der(11)t(11;15)(q23;q15),add(12)(q13),ins(14;?)(q13;?),-15,+mar. Combined with several previously reported studies, these aberrations could not identify a common cytogenetic abnormality in OFMT.

Ossifying fibromyxoid tumor of soft parts presenting as a scalp cyst

Ossifying fibromyxoid tumor of soft parts (OFMT) is a rare mesenchymal neoplasm of intermediate malignant potential. The tumor most commonly occurs on the extremities with a male predominance. We present an unusual case of OFMT occurring as a cystic lesion on the scalp of a female. A 67-year-old woman presented with a 6-year history of a well demarcated cystic scalp mass. Physical examination revealed a slightly movable, multilobular mass of the left parietal scalp which was subsequently excised. Histological evaluation revealed an OFMT comprised of bland, small cells and a thick collagenous capsule containing an incomplete rim of lamellar bone. OFMT is an unusual tumor which can usually be considered as having an intermediate risk of malignancy. It generally occurs in the extremities with a male predominance. The clinical differential for a cystic mass on the scalp is broadened by this unusual case of an OFMT.

Ossifying fibromyxoid tumor of soft parts is disease free for 7 years after tumor resection

We reported a case of the ossifying fibromyxoid tumor of soft parts which occurred in the anterior chest wall in a 70-year-old Japanese woman. Radiographic examination revealed that it demonstrated a large oval mass with well-circumscribing shell-like margin. Macroscopic findings showed that the specimen revealed a multi-lobular structure with surrounding bone formation. Spindle or oval hypocellular fibroblastic cells in a myxoid background were observed in the histological examination. Those cells were positive for keratin and S-100 protein. On these bases, the tumor was diagnosed as an ossifying fibromyxoid tumor of soft parts. No local recurrence of the tumor has been observed at seven years postoperatively. As the histogenesis and the clinical characteristic of the tumor remained obscure, total tumor resection and regular clinical follow up has to be the appropriate management of the tumor at present.

Ossifying fibromyxoid tumor of soft parts: a clinicopathologic study of 70 cases with emphasis on atypical and malignant variants.

The ossifying fibromyxoid tumor of soft parts (OFMT) is an uncommon soft tissue neoplasm of uncertain lineage. Approximately 100 cases of OFMT have been reported. Although the majority behave in a benign fashion, very rare tumors with histologic and clinical evidence of malignancy have been reported. Criteria for malignancy in OFMT have not as yet been defined. Seventy cases of OFMT were retrieved from our consultation archives and studied with respect to patient age and sex, tumor site and size, growth pattern, percentage of typical OFMT, cellularity and nuclear grade, mitotic figures (MF)/50 high power fields (HPF), atypical mitoses, necrosis, vascular invasion, and the presence of bone. Immunohistochemistry for pancytokeratin, S-100 protein, smooth muscle actin, desmin, and collagen II was performed on a subset of cases. Follow-up information was obtained from the submitting pathologists and clinicians. The Fisher exact test was used for statistical analysis. Patients (39 male, 31 female) ranged in age from 14 to 83 years (median 49 years). The tumors occurred primarily as subcutaneous or deeply seated masses in the trunk and proximal extremities and ranged from 1 to 14 cm (median 4.0 cm). The percentage of typical OFMT present in each case ranged from 0% to 100% (median 70%), and bone was present in 44 cases (63%). Mitotic activity ranged from 0 to 40 MF/50 HPF (median 2 MF/50 HPF), necrosis was present in 12 cases (17%), and vascular invasion was seen in 8 cases (11%). High cellularity or high nuclear grade was seen in 14 and 13 cases, respectively. Immunohistochemical results were as follows: S-100 protein (33 of 55, 60%), pancytokeratin (5 of 48, 10%), smooth muscle actin (2 of 44, 5%), desmin (5 of 39, 13%), and collagen II (1 of 26, 4%). Follow-up (51 cases, mean 54 months, median 36 months, range 5-151 months) showed local recurrences in nine patients and metastases in eight patients. Currently, 41 patients are disease free, 6 are alive with disease, 4 are dead of disease, and 1 died of other causes. The presence of high cellularity (p = 0.002), high nuclear grade (p = 0.001), or >2 MF/50 HPF (p = 0.004) were significantly associated with the development of metastatic disease and local recurrence. Infiltrative growth was also associated with increased risk of local recurrence (p = 0.03). We conclude that the histologic spectrum of OFMT is broader than previously appreciated, as many clinically benign cases display moderate cellularity, nuclear enlargement, or have identifiable mitotic figures. Our results strongly suggest that OFMT with 1) high nuclear grade or 2) high cellularity and mitotic activity of >2 MF/50 HPF should be regarded as sarcomas with significant potential for metastasis and untoward outcome ("malignant OFMT"). The remainder can be considered within the spectrum of OFMT, recognizing that even these lesions possess a risk, albeit very low, of metastasis. Consequently, OFMT should be considered tumors of intermediate malignancy. Their line of differentiation remains unclear, although we suggest they may belong to the category of translocation-associated sarcomas, not all of which recapitulate a normal line of differentiation.

Ossifying Fibromyxoid Tumor of Soft Parts: An Unusual Pediatric Case

We report a case of a 3-year-old female child with an ossifying fibromyxoid tumor of soft parts, the youngest such case to be reported to date. The young age of this patient raises the possibility that the tumor may be congenital arising in developmentally deranged Schwann cells from the neural crest (because of its paraspinous location). This presentation may be unique in this case, or it could be that the usual adult variations represent malignant change in embryologic rests of Schwann cells derived from abnormal neural crest cells.

Ossifying fibromyxoid tumor of soft parts: report of a case with novel cytogenetic findings

A slowly growing tumor of the left thenar region in a 40-year-old man had the classic features of an ossifying fibromyxoid tumor of soft parts, including an incomplete shell of lamellar bone; a center composed of nodular aggregates of small spindled, oval, and stellate cells in abundant myxoid stroma; and strong expression of vimentin, S-100, and neuron-specific enolase by the tumor cells. Clonal chromosomal abnormalities included loss of a chromosome 6, extra material of unknown origin attached to the long arm of chromosome 12, and an unbalanced translocation involving the short arm of a chromosome 6 and the long arm of a chromosome 14. The karyotype was interpreted as 45,XY, der(6;14)(p10;q10),add(12)(q24.3). The chromosomal abnormalities suggest osteochondroblastic rather than neuronal or schwannian lineage.

Ossifying fibromyxoid tumor of soft parts in a child: A case report

Ossifying fibromyxoid tumor (OFMT) is a relatively rare tumor, most of which occur in adults with preferential localization in subcutis or muscles of the extremeties. Although Schwannian or cartilage origin has been suggested, histogenesis of this tumor still is unclear. The authors present a 6-year-old girl with retroperitoneal OFMT showing paraspinal extension, who is alive and tumor free 9 years after excision. The current case is the youngest reported patient showing unusual deep trunk site with surgically identified association with the spinal nerve. Both the clinical and histopathologic features strongly suggested Schwannian origin of this tumor.

Ossifying fibromyxoid tumour of soft parts: report of four cases including one mediastinal and one infantile.

Four cases of ossifying fibromyxoid tumour of soft parts are described. One of them was in the mediastinum, a hitherto unreported location of this rare neoplasm. Another was removed from the subcutaneous tissue of the head of a two-year-old girl, the youngest patient so far described. A peculiar feature of this tumour was haphazard spindle cell groups showing smooth muscle differentiation. One tumour was remarkably proliferative with 20 mitotic figures per 10 high power fields and 50% of cells positive for Ki-67 antigen. Immunohistochemical analysis revealed that all the tumours were diffusely positive for vimentin, and focally for S-100-protein. In addition to this the infantile tumour expressed focal alpha-smooth muscle actin, desmin and glial fibrillary acidic protein, while the mediastinal tumour expressed only alpha-smooth muscle actin and the highly proliferative one expressed none of these antigens. Background cells, including histiocytes, lymphocytes and mast cells were numerous. DNA cytometry analysis using both static and flow methods showed that the mediastinal tumour contained two cell clones, while the others were diploid. The proliferative fraction of cells (S plus G2 phases) was prominent in the proliferative and infantile tumours.

Bone scan in ossifying fibromyxoid tumor of soft parts.

A 32-year-old man presented with a firm, nonmobile, slightly tender mass (5 cm in size) in the left posterior chest wall that had been slowly increasing in size over the past 5 years. After radiographic, CT, and scintigraphic evaluation, the tumor was resected and initially was histologically misinterpreted as a mesenchymal hamartoma, a benign lesion not requiring further management. After one year, the tumor recurred locally and a repeat histologic examination proved it to be an ossifying fibromyxoid tumor of soft parts, a recently defined rare, potentially malignant neoplasm with histologically unique features showing areas of mature bone formation within a soft tissue mass.

Ossifying fibromyxoid tumor of soft parts: a report of 17 cases with emphasis on unusual histological features.

Ossifying fibromyxoid tumor of soft parts is an unusual benign neoplasm, with a tendency for local recurrence. Its typical microscopic appearance is that of a multinodular proliferation of round to spindle shaped cells separated by fibrous bands in which bone formation is often seen. Herein, we present the clinicopathologic features of 17 examples of this tumor with particular emphasis on some unusual histopathologic features that may place pitfalls in the diagnosis of this tumor, including satellite micronodules, mucinous microcysts, absence of myxoid areas, crush artifact, multiple microcalcifications, epidermoid cysts, atypical chondroid differentiation with binucleate lacunar cells, pericytic growth pattern, and malignant change. Awareness of these unusual morphologic features should lead to a search for areas displaying the more typical features of ossifying fibromyxoid tumor to arrive at a correct diagnosis.

Ectomesenchymal chondromyxoid tumor of the anterior tongue. Nineteen cases of a new clinicopathologic entity.

We present 19 cases of a previously undescribed myxoid tumor of the anterior tongue. These lesions occurred in nine women and 10 men aged 9 to 78 years (median, 32 years). Most tumors were seen as slow growing, painless nodules in the anterior dorsal tongue. The duration of growth ranged from a few months to 10 years. All tumors were treated by surgical excision, and two recurred. Microscopically, they exhibited a lobular proliferation of ovoid and fusiform cells, which often had multilobated nuclei and occasional foci of atypia, in a chondromyxoid background. Some tumors entrapped muscle or nerve fibers and had a tendency for blunt infiltration of adjacent tissue. The cells were diffusely and intensely immunoreactive for glial fibrillary acidic protein (GFAP) and cytokeratin but were decorated less frequently with antibodies for smooth muscle actin and S-100 protein. Reactivity for epithelial membrane antigen and desmin was not found. We believe these tumors fail to meet established clinicopathologic criteria for any existing myxoid neoplasms of the tongue, including nerve sheath myxoma, myoepithelioma, benign mixed tumor, ossifying fibromyxoid tumor of soft parts, extraskeletal myxoid chondrosarcoma, and glial and chondroid choristomas or heterotopias. Although the histogenesis of this neoplasm is unclear, we suspect that a cell of undifferentiated ectomesenchyme is the progenitor and suggest the descriptive term ectomesenchymal chondromyxoid tumor (ECT) of the anterior tongue be adopted.

Ossifying fibromyxoid tumor of soft parts: A morphological and immunohistochemical study

A case is presented of ossifying fibromyxoid tumor of soft parts (OFMTSP) which occurred in the left cheek of a 59 year old Chinese woman. Histologically, the tumor was located in the subcutis with a fibrous pseudocapsule that contained discontinuous rims of mature trabecular bone. The tumor cells were small, round to ovoid with a uniform, round nucleus and a pale or slightly eosinophilic cytoplasm. Most of the cells were arranged in a random manner, some in a vague lace-like pattern. Mitotic figures were extremely rare. The stroma appeared fibromyxoid with scattered foci of mucinous lakes. Immunohistochemically, most of the neoplastic cells displayed immunoreactivities for S-100 protein, S-100 protein alpha, vimentin and alpha-smooth muscle actin; many tumor cells were positive for desmin. The tumor also showed stromal immunoreactivity for type IV collagen and was negative for cytokeratins, epithelial membrane antigen, glial fibrillary acidic protein, neurofilaments, muscle-specific actin, Leu-7, myelin-basic protein, osteocalcin and melanoma-specific antigen. The immunophenotypes expressed by the present OFMTSP seem to reflect two lineages of neoplastic cell differentiation, that is of nerve sheath and of smooth muscle; at the present stage, it is premature to diagnose this lesion as either nerve sheath or smooth muscle tumor.