Myxoid dermatofibroma on a great toe: a case report

Dermatofibroma is a common benign fibrohistiocytic tumor with many clinicopathological variants. Myxoid dermatofibroma is one of these variants, which is characterized by marked stromal mucin deposition. This report presents a case of myxoid dermatofibroma on a great toe that had been slowly growing for two years. Histopathologically, the relatively well-circumscribed dermal tumor was separated from the epidermis by a small grenz zone. The tumor tissue consisted of oval to spindle-shaped cells with well-defined cell borders and spindly condensed nuclei. No cytologic atypia or mitotic figures were found. Although most of the tumor cells were embedded in a prominently myxoid stroma, typical features of classic dermatofibroma including a storiform growth pattern and more densely packed collagen were observed at the periphery. Immunohistochemically, the tumor cells showed positive staining for CD68 and CD99, and negative staining for CD34 and S-100. Histopathological differential diagnoses of myxoid dermatofibroma include soft tissue neoplasms with myxoid tumor stroma, such as superficial acral fibromyxoma, cellular digital fibroma, superficial angiomyxoma, myxoid dermatofibrosarcoma protuberans and low-grade fibromyxoid sarcoma. Immunohistochemical staining can be useful in the differential diagnosis of these tumors. This case highlights the challenges encountered in the histopathological interpretation of myxoid dermatofibroma. Pathologists should keep in mind the diagnosis of myxoid dermatofibroma when dealing with myxoid neoplastic lesions arising on acral sites.     

Parachordoma: a recurrent case and review of the literature

Parachordoma is an uncommon tumor of soft tissue, and the origin is not clear. Recurrence and metastasis are rarely seen. A piecemeal mass measuring 7x4x3 cm was excised from a 28-year-man who had presented with pain and swelling of the right shoulder for 5 years. Histopathologically, the tumor was composed of cells with clear eosinophilic cytoplasm and an epithelioid appearance in a myxoid stroma separated by fibrous tissue with mild pleomorphism and mitotic activity. Tumoral cells were immunoreactive for cytokeratin 8/18, EMA, S-100 and vimentin, immunohistochemically. Recurrence was seen one year after the initial diagnosis. Areas of increased mitotic activity and atypical mitoses were observed in the recurrent tumor. We report this case as recurrence occurred earlier than usual and exhibited malignant features.     

Extra-axial soft tissue chordoma of wrist

Extra-axial soft tissue chordoma is rare. We report a case of extra-axial soft tissue chordoma of the right wrist in an 87-year-old man. The tumor was large, and the cut surface showed multinodular and myxoid appearance. Microscopically, nests of epithelioid and spindle cells were observed in the myxoid matrix. Vacuolated cells were also observed. The tumor cells were diffusely positive for brachyury and cytokeratin 19 on immunohistochemistry, suggesting that the tumor was extra-axial soft tissue chordoma. Extra-axial chordoma is the same entity as chordoma periphericum (parachordoma), as proposed by Laskowski and Dabska.     

Chordomalike Soft Tissue Sarcoma in the Leg: A Light and Electron Microscopic and Immunohistochemical Study

A soft tissue tumor in the leg of a 67-year-old woman is described. This large tumor below the knee area infiltrated extensively the deep and superficial soft tissues but did not involve the bones. The tumor cells formed nodules resembling the architecture seen in chondroid tumors and chordoma. The tumor cells were often vacuolized, and there was extracellular myxoid matrix similar to that in chordoma or myxoid chondrosarcoma. Immunohistochemistry showed keratins 8 and 19, epithelial membrane antigen, and vimentin in most tumor cells, and there was also S-100 protein positivity in a number of tumor cells. Electron microscopy showed desmosomelike cell junctions and bundles of intermediate filaments resembling those seen in many epithelial neoplasms. Thus the tumor resembled chordoma in many respects. Because clinically no other primary tumor was found, this tumor is probably a chordomalike primary soft tissue sarcoma different from typical extraskeletal myxoid chondrosarcoma or chordoid sarcoma.     

Chordomalike Soft Tissue Sarcoma in the Leg: A Light and Electron Microscopic and Immunohistochemical Study

A soft tissue tumor in the leg of a 67-year-old woman is described. This large tumor below the knee area infiltrated extensively the deep and superficial soft tissues but did not involve the bones. The tumor cells formed nodules resembling the architecture seen in chondroid tumors and chordoma. The tumor cells were often vacuolized, and there was extracellular myxoid matrix similar to that in chordoma or myxoid chondrosarcoma. Immunohistochemistry showed keratins 8 and 19, epithelial membrane antigen, and vimentin in most tumor cells, and there was also S-100 protein positivity in a number of tumor cells. Electron microscopy showed desmosomelike cell junctions and bundles of intermediate filaments resembling those seen in many epithelial neoplasms. Thus the tumor resembled chordoma in many respects. Because clinically no other primary tumor was found, this tumor is probably a chordomalike primary soft tissue sarcoma different from typical extraskeletal myxoid chondrosarcoma or chordoid sarcoma.     

子宫黏液样平滑肌肉瘤的临床病理诊断

目的 :探讨子宫黏液样平滑肌肉瘤 (MLU)的临床病理特征及诊断、鉴别诊断要点。方法 :对 1例MLU进行大体、光镜及免疫组化观察 ,并复习相关文献。结果 :MLU的临床症状是盆腔包块及不规则阴道流血 ;其突出的病理特征是肿瘤切面呈弥漫性胶冻状外观 ,镜下见大量奥辛蓝阳性的黏液样基质 ,瘤细胞大部分梭形显平滑肌细胞分化 ,并浸润周围正常平滑肌组织和血管腔 ;免疫组化 :瘤细胞HHF35 ( )。结论 :MLU是子宫平滑肌肉瘤的一个罕见变型 ;由于大多数MLU缺乏细胞异型性和核分裂象计数很低 ,常易引起病理误诊 ,在冷冻切片中更是如此。鉴别诊断必须首先区别常见的子宫平滑肌瘤黏液变性或水肿变性 ,其次还应与任何黏液样软组织恶性肿瘤相鉴别     

Myxoid solitary fibrous tumor: a clinicopathologic study of three cases

While focal myxoid areas are occasionally observed in solitary fibrous tumors, neoplasms of this type exhibiting extensive myxoid change are considered exceedingly uncommon. Due to their rarity, the biologic behavior of myxoid solitary fibrous tumor has not been determined. Three cases of myxoid solitary fibrous tumor are described in order to better characterize the clinical and pathologic features of this uncommon variant of solitary fibrous tumor. The tumors occurred in one man and two women, with ages of 37, 47, and 58 years, respectively. Sites of involvement included the retroperitoneum, pelvis, and soft tissue of the neck. Histologically, all cases were characterized predominantly by the presence of myxoid stroma comprising 70% to 100% of the tumor. The tumor cells were predominantly spindled in all cases, and arranged randomly, in loose fascicles, or in anastomosing strands imparting a microcystic/reticular appearance. The lesional cells had a bland cytologic appearance and low mitotic count. All tumors lacked necrosis and areas of increased cellularity. By immunohistochemistry, all cases were positive for CD34, CD99, and bcl-2, and negative for keratin, epithelial membrane antigen, desmin, actin, smooth muscle actin, and S-100 protein. To date, all cases have followed a benign course without evidence of recurrence or metastasis with a follow-up duration ranging from 50 to 87 months. The data suggest that myxoid solitary fibrous tumors are associated with an indolent clinical course and favorable prognosis.     

Myxoid leiomyosarcoma

A series of 13 myxoid leiomyosarcomas (LS) is presented. Seven were from genital and six from extragenital sites and most tumours were large. The myxoid matrix in some tumours separated individual tumour cells; occasionally the myxoid areas were trabecular in shape, resulting in a plexiform tumour pattern; in other tumours there were many closely spaced small mucoid pools which produced a pseudoglandular pattern; in one tumour the pools were large and confluent, and macroscopically evident as gelatinous areas. Four patients who were followed up and whose tumours had shown an absent or very low mitotic rate, nevertheless developed recurrences or metastases; hence a low mitotic count was an unreliable prognostic criterion. The myxoid LS studied did not differ in clinical behaviour and prognosis from the more common solid counterparts. Myxoid LS should be included in the differential diagnosis of any myxoid malignant soft tissue tumour.     

Pleomorphic hyalinizing angiectatic tumor with a sarcomatous component recurring as high-grade myxofibrosarcoma

Pleomorphic hyalinizing angiectatic tumor (PHAT) of the soft tissue is a rare distinctive tumor listed as a benign neoplasm in the new World Health Organization classification. It may recur and most reported recurrent tumors retained the typical morphological appearance of PHAT; rare tumors recurred with the appearance of a sarcoma. Reported herein is an additional example of recurrent PHAT, but in contrast to the previously described cases the present tumor morphologically qualified as a sarcoma from the very beginning; it recurred as a high-grade myxofibrosarcoma. A 76-year-old woman presented with a solitary subcutaneous tumor in the axilla that was surgically removed. Seven months later, the patient experienced a local recurrence. Microscopically, the typical features of PHAT were identified in the initial lesion, namely hyalinized, fibrin-containing vessels and pleomorphic stromal cells; there were areas of hemorrhage and necrosis. Additionally, peripherally located areas of the tumor manifested highly pleomorphic cells with frequent atypical mitoses, producing a sarcomatous appearance. The mitotic index in the sarcomatous part was 1/10 high-power fields (HPF). Hyalinized, fibrin-containing vessels were absent in these sarcomatous areas, and the stroma was myxoid. The recurrent lesion was composed of large highly pleomorphic oval, round, spindled or bizarre cells with a high mitotic rate, ranging from 3/10 HPF to 7/10 HPF. The neoplastic cells were arranged haphazardly in a myxoid matrix. Hyalinized, fibrin-containing vessels typical for PHAT were absent. PHAT may be more aggressive than previously thought, and PHAT may encompass a morphological spectrum of the lesion ranging from benign to malignant.     

Basal cell adenocarcinoma arising from the minor salivary gland in the soft palate: a case report

Basal cell adenocarcinomas (BCACs) of the oral minor salivary gland are very rare neoplasms. We report on an 86-year-old woman with BCAC arising from the minor salivary gland in the soft palate. Histologically, the tumor was located in the submucosa and showed microinvasion into the adjacent soft tissue without encapsulation. It contained tiny tumor islands with solid and tubular patterns, as well as myxoid stroma. The neoplastic cells were basaloid cells and were composed of large pale cells and small dark cells. They were positive for alpha-smooth muscle actin, cytokeratin 14, and vimentin in the periphery of the tumor island, showing a myoepithelial differentiation. The myxoid stroma was positive for alcian blue and colloidal iron. Apical membranes of the neoplastic cells were positive for MUC1 and CEA. The present case is the 14th documented case of oral BCAC (the fifth case of palatal BCAC).     

Extraskeletal myxoid chondrosarcoma of the nasopharynx

Extraskeletal myxoid chondrosarcoma is a rare but distinct entity with special clinicopathological, immunohistochemical, cytogenetical and outcome features. This tumor developed from soft tissues. A few cases have been reported in the head and neck in the literature. We report two new cases of extraskeletal myxoid chrondrosarcoma presenting in such an unusual site: one involved the left nasal cavity of a 67-year-old man and the second the sphenoidal sinus of a 71-year-old woman. The microscopic examination revealed nests of round small cells dispersed in a myxoid stroma. The myxoid material was stained with Alcian Blue with and without hyaluronidase application whereas no PAS staining was observed. The immunohistochemical staining showed reactivity with S-100 protein and vimentin in two cases and with EMA in one case. These results allowed us to exclude other differential diagnoses: soft tissue tumors with a myxoid stroma (myxoma, myxoid liposarcoma and myxofibrosarcoma). No staining with anti-KL1 allowed us to exclude chordoma. Curative surgery was not possible. Both patients were given radiotherapy and the tumor regressed in one.     

Myxoid endometrial stromal sarcoma of the uterus

A rare case of a myxoid type of endometrial stromal sarcoma of the uterus in a 41-year-old woman is reported. A tumor was found in the myometrium and was well circumscribed, measuring 9 x 7 x 7 cm in size. The tumor was mainly composed of a hypocellular area with tumor cells separated by prominent myxoid stroma. The tumor cells were spindle-shaped and resembled endometrial stromal cells. Numerous small thin-walled vessels were seen throughout the tumor. Immunohistochemically, the tumor cells were diffusely stained for estrogen and progesterone receptors and CD10, and focally and weakly for HHF35, alpha-smooth muscle actin and desmin, but not stained for h-caldesmon. These results indicated that the tumor originated from endometrial stromal cells. The tumor had an increased mitotic activity (MIB-1 labeling index: 1-10%), and focally showed nuclear pleomorphism. Thus, this tumor had a malignant potential and was diagnosed as a myxoid type of low-grade endometrial stromal sarcoma. The patient is currently well with no evidence of local recurrence or metastasis 21 months after the operation. This case indicates a wide morphological spectrum of endometrial stromal tumor. A myxoid endometrial stromal sarcoma should be considered in the different diagnosis of the intramural myxoid tumors in the uterus.     

Cytologic findings of myxoid neurothekeoma: case report based on fine-needle aspiration cytology,immunohistochemistry, and correlating histopathology

Myxoid neurothekeomas (nerve sheath myxomas) are rare benign cutaneous neoplasms that may morphologically mimic other myxoid neoplasms of skin and soft tissue. The cytologic and histopathologic features of this lesion may resemble various myxoid sarcomas, chordoma, myxoid neurofibroma, dermal cutaneous mucinosis, and cutaneous myxoma as well as other myxoid or chondroid neoplasms. In this study, a myxoid neurothekeoma was analyzed using multiple techniques. We found that myxoid neurothekeomas reveal a nonspecific pattern by fine-needle aspiration, including stellate cells embedded within an abundant metachromatic myxoid stromal matrix. These are cytologic features shared by various other subcutaneous neoplasms and thus may not be helpful in forming a definitive diagnosis. Histopathologically, the tumor is composed of nodules of myxoid stroma containing interspersed bland spindled and stellate cells. Immunohistochemical studies show tumor cell positivity for S-100 protein and vimentin, a profile shared by other neoplasms with similar cytologic features and therefore of little diagnostic value. The histologic and cytologic differential of subcutaneous and soft tissue myxomatous lesions is broad and, therefore, is of unique value to the cytopathologist to consider myxoid neurothekeomas among the differential of other myxomatous neoplasms.     

An undifferentiated sarcoma in a rat resembling extraskeletal myxoid chondrosarcoma in man

A soft tissue tumor occurring in the inguinal subcutaneous tissue was detected in a 109-week-old male F344 rat. Macroscopically, the tumor mass showed no skeletal relationship and a gelatinous multinodular appearance. Histologically, the tumor consisted of irregular lobules separated by scant fibrous septa. In each lobule, tumor cells were arranged in cords and strands in the plentiful myxoid stroma. The tumor cells showed marked pleomorphism, and had large, round to ovoid nuclei and abundant eosinophilic cytoplasm. Mitotic figures were often seen. Myxoid stroma of the tumor contained a large amount of acid mucopolysaccharides and collagen type II, which were demonstrated by histochemistry and immunohistochemistry respectively. The tumor cells showed positive immunoreactivities for vimentin and S100 protein. Ultrastructural examination revealed that the tumor cells had a large amount of mitochondria, Golgi complex and dilated rough endoplasmic reticulum containing amorphous material, and the myxoid stroma contained collagenous fibrils and proteoglycan particles. Based on these results, the present tumor in a rat resembled extraskeletal myxoid chondrosarcoma in man.     

Myxomatous soft tissue tumors: correlation of cytopathology and histopathology.

A small, uncommon group of soft tissue tumors are distinguished by their unique and consistent ability to produce an overwhelming abundance of myxoid ground substance along with the proliferating cells that constitute the tumor. Grossly, all these neoplasms have a variable gelatinous quality. Because of the voluminous stroma, most of these tumors have some findings that overlap with one another. Nonetheless, each tumor has a composite set of morphologic, immunophenotypic, ultrastructural, and genotypic features exclusive to itself. Because soft tissue masses are not a frequent site of fine-needle aspiration, the cytopathology of this set of tumors is vastly unappreciated, both in the literature and in day-to-day practice. The aim of this review is to detail the salient light microscopic findings of this group of six major myxoid soft tissue tumors, to correlate the cytopathology (particularly as obtained using the fine-needle aspiration biopsy technique) with its histopathologic counterparts, and to discuss the limitations of both cytologic and histologic methods. This cytohistopathologic correlation should assist the reader in the diagnosis of myxoid tumors of soft tissue.     

Vascular tumors of bone: A study of 17 cases other than ordinary hemangioma,with an evaluation of the relationship of hemangioendothelioma of bone to epithelioid hemangioma,epithelioid hemangioendothelioma,and high-grade angiosarcoma

Cases filed as vascular tumor of bone other than ordinary hemangioma were reviewed. They were included in the study if there was adequate histologic material and clinical information, clear evidence of bone origin, and at least 5 years follow-up. The study group comprised 17 cases, of which 13 were categorized as hemangioendothelioma of bone, 1 as epithelioid hemangioendothelioma, and 3 as high-grade angiosarcoma. Hemangioendothelioma of bone had growth patterns varying from vasoformative to solid, but well-formed vessels were present in at least some area in all cases. The cells generally had a rounded, epithelioid character, regular nuclei, and relatively few mitotic figures; occasional features included spindle cells and scattered enlarged, hyperchromatic or pleomorphic nuclei. Lymphoplasmacytic and eosinophilic inflammatory infiltrate ranged from prominent to slight or absent, and myxoid or hyaline stroma was never more than focal. Epithelioid hemangioma could not be separated from hemangioendothelioma of bone. The single epithelioid hemangioendothelioma for the most part had cords of relatively uniform epithelioid cells in a prominent myxoid stroma but focally demonstrated an angiosarcoma-like appearance, with irregular vascular spaces and marked nuclear pleomorphism. The high-grade angiosarcomas exhibited predominantly irregular vasoformation combined with solid areas, diffuse nuclear hyperchromatism and pleomorphism, and, in 2 cases, numerous mitotic figures (the third case had only a small biopsy and a postradiation amputation specimen). Of the hemangioendotheliomas of bone, 7 were unicentric and 6 were regionally multicentric either concurrently or sequentially. Three patients had intraosseous local recurrence, 2 had discontinuous regional skin or soft tissue involvement (including the popliteal artery in 1), and 1 had a solitary lung metastasis, but none died of tumor. The patient with epithelioid hemangioendothelioma had multicentric tumors in widely separated bones and died with liver and lung metastases. Two of the high-grade angiosarcomas were unicentric, and the third was regionally multicentric, with a popliteal artery-soft tissue component as well. All 3 of these patients died with metastases in various sites.     

Parachordoma of the tibia: report of a rare case

We report a case of recurrent parachordoma of the left anterior tibial region in a 64-year-old male patient. The tumor was a periosteal tender mass, and, histologically, displayed vague nodules of spindle to rounded eosinophilic cells embedded in a myxoid matrix. Large vacuolated (physalphorouslike) cells were noted as in sacrococcygeal chordoma. This tumor should be differentiated from myxoid chondrosarcoma, myxoid liposarcoma, chondromyxoid fibroma, and metastatic chordoma. The presence of physaliphorous cells in the tumor with positive immunoreactions caused by cytokeratin rules out the diagnosis of another myxoid tumor. The differential diagnosis from metastatic chordoma is basically made by clinicians. Even though parachordoma is usually regarded as a benign soft tissue neoplasm, two recurrences occurred in our case. Since the reported cases, including ours, have diverse clinical courses, it is essential to follow-up the patient carefully.     

Primitive myxoid mesenchymal tumor of infancy: report of two cases and review of the literature

Primitive myxoid mesenchymal tumor of infancy is a recently recognized soft tissue tumor with only a few cases reported. Here, we reported another two cases of the lesion, a 5-month-old boy presenting with a soft tissue mass in the neck region that recurred 2 months later and a 3-day-old girl with a congenital superficial dorsal lumbar mass that extended to the spinal canal 1 month later. They shared similar histological patterns, such as unusual diffuse myxoid background, delicate vascular network, small cystic spaces, low to moderate cellularity, and primitive mesenchymal tumor cells. Immunohistochemically, the tumor cells showed positive for vimentin, CD99, CD117 and nestin, negative for myoid, lipoblastic, histiocytic, and neural markers. In conclusion, primitive myxoid mesenchymal tumor of infancy is a distinctive entity with its own clinical pathological features. Expression of CD99, CD117 and nestin may be consistent with the primitive nature of the tumor and may serve as ancillary markers for differential diagnosis from the other infantile tumors.     

Fine‐needle aspiration features of ossifying fibromyxoid tumor in the breast: A case report and literature review

Ossifying fibromyxoid tumor (OFT) is a very rare soft tissue tumor which is characterized by incomplete peripheral mature bone shell. To date, cytological features of OFT have been poorly studied with only seven case reports. In this study, an additional case of OFT investigated by fine‐needle aspiration is presented. A 75‐year‐old man with advanced nasopharyngeal carcinoma presented with peripherally calcified right breast mass. Smears were hypercellular and stroma‐rich. Tumor cells were mainly dispersed, with epithelioid morphology and eccentrically located nuclei. In the background, there was abundant eosinophilic myxoid secretion. No necrosis, atypia, or mitotic activity was found. The tumor showed diffuse S‐100, CD10, STAT6 expression and focal desmin, estrogen receptor (ER), and progesteron receptor (PgR) expression. Fluorescence in situ hybridization study revealed PHF1 rearrangement in 9% of cells. Cytological characteristic of OFT is quite distinctive and precise diagnosis can be made, especially when it is coupled with compatible radiological findings.