Fine-needle aspiration cytology of low-grade fibromyxoid sarcoma of the renal capsule (capsuloma)

We report on the fine-needle aspiration (FNA) findings of a low-grade fibromyxoid sarcoma arising from the renal capsule in a 70-yr-old male. Cytologic examination revealed a spindle-cell and myxoid lesion characterized by microtissue fragments of delicate spindle-shaped cells and thin-walled capillary-type channels enmeshed in metachromatically staining myxoid material, best appreciated in Diff-Quik-stained smears. The spindle cells had slightly elongated, bland, oval to tapered nuclei. Based on the FNA diagnosis, the renal mass was resected, which revealed a hypocellular to moderately cellular, spindle-shaped neoplasm showing alternating hypercellular fibrous foci with hypocellular myxoid areas arranged in a swirling growth pattern, characteristic of low-grade fibromyxoid sarcoma. We believe that this is the first report of a low-grade fibromyxoid sarcoma arising in the renal capsule (capsuloma), as well as the first capsuloma diagnosed by FNA biopsy. Differential diagnoses of other sarcomas arising from the kidney and nearby retroperitoneal region are discussed, as well as other entities that might enter into the differential diagnosis of this low-grade sarcoma.     

Plexiform myxoid gastrointestinal stromal tumor: a potential diagnostic pitfall in pathological findings

Gastrointestinal stromal tumors (GISTs) have a rather wide morphologic spectrum. Here, we report a rare variant plexiform GIST in gastric antrum. Microscopically, the tumor showed plexiform or multinodular growth pattern, proliferation of spindle cells, presence of epithelioid cells, and abundant myxoid stroma with thin-walled blood vessels. The histologic features were similar to plexiform fibromyxoma. The typical characteristics of immunohistochemistry (positive for CD34, DOG-1 and CD117) confirmed the final diagnosis of GIST. This is a rare case of myxoid GIST characterized by a plexiform growth pattern.     

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.     

Myxoid synovial sarcoma: an underappreciated morphologic subset.

Focal myxoid change is a well-recognized feature of synovial sarcoma, but the presence of a predominantly myxoid stroma is rare. We describe seven cases of myxoid synovial sarcoma in which marked myxoid change initially obscured the diagnosis, leading to confusion (principally with malignant peripheral nerve sheath tumor). The median age (20 yr) and tumor location (four lower extremity, two upper extremity, and one head and neck region) were similar to those found in typical synovial sarcoma. Histologically, five cases were monophasic spindle cell lesions with a lacy appearance in areas with a prominent Alcian blue-positive myxoid stroma. Each case had foci with more typical features of synovial sarcoma, including a fascicular growth pattern with a variably collagenized stroma, stromal mast cells, a hemangiopericytoma-like vascular pattern, and calcification. Two cases showed small foci of glandular (biphasic) differentiation. Immunohistochemically, all of the seven cases were positive for epithelial membrane antigen, four of six were positive for pan-keratin, three of six were positive for S-100, two of four were positive for CD99, and six of six were negative for desmin. Clinical follow-up in six cases ranged from 8 to 48 months (median, 21 mo). Local recurrence developed in three patients at 9, 20, and 24 months, respectively. In one of these three patients, lung metastases developed at 13 months, and the patient died of disseminated disease at 23 months. In another of the three patients, lung metastases developed at 27 months. Three patients had no evidence of disease at 8, 15, and 15 months. Our data are too limited to indicate any clinical differences between myxoid synovial sarcoma and conventional synovial sarcoma Recognition of this rare histologic variant of synovial sarcoma is important because it can easily be mistaken for other myxoid spindle cell neoplasms, potentially resulting in suboptimal therapy.     

Rapidly-growing nodular pseudoangiomatous stromal hyperplasia of the breast: case report

Pseudoangiomatous stromal hyperplasia is a benign proliferative lesion of the mammary stroma that rarely presents as a localized mass. Pseudoangiomatous stromal hyperplasia is characterized by a dense, collagenous proliferation of the mammary stroma, associated with capillary-like spaces. Pseudoangiomatous stromal hyperplasia can be mistaken with fibroadenoma on radiological examination or with low-grade angiosarcoma on histological examination. Its main importance is its distinction from angiosarcoma. The presented case was a 40-year-old woman who was admitted with a rapidly growing breast tumor. Physical examination revealed an elastic-firm, well-defined, mobile and painless mass in her right breast. Mammograms revealed a 6.7 x 3.7 cm, lobulated, well-circumscribed mass in her right breast but no calcification. Sonographic examination showed a well-defined and homogenous mass, not including any cyst. Based on these findings, a provisional diagnosis of fibroadenoma was made. Considering the rapid growth history of the mass, tumor excision was performed. The excised tumor was well demarcated and had a smooth external surface. Histological examination revealed the tumor to be composed of markedly increased fibrous stroma and scattered epithelial components (cystic dilatation of the ducts, blunt duct adenosis). The fibrous stroma contained numerous anastomosing slit-like spaces. Isolated spindle cells appeared intermittently at the margins of the spaces resembled endothelial cells. Immunohistochemical staining showed that the spindle cells were positive for CD34 and negative for Factor VIII-related antigen. The lesion was diagnosed as nodular pseudoangiomatous stromal hyperplasia.     

Low-grade fibromyxoid sarcoma: an unusual cardiac location

We report the unusual cardiac localization of a primary low-grade fibromyxoid sarcoma of the right ventricle in a 57-year-old woman. Histological examination revealed a prevalent myxoid appearance with whorling growth pattern of small or spindle cells with bland features alternating with rare more collagenous hypocellular areas with rare atypical cells. Genomic polymerase chain reaction of genomic DNA revealed the typical FUS/Creb3L2 fusion gene products typical of low-grade fibromyxoid sarcoma. The tumor was surgically removed and recurred after 7 years as high-grade pleomorphic sarcoma. The patient died 6 months after the clinical manifestation of recurrence. Low-grade fibromyxoid sarcoma of soft tissues is a rare, distinctive variant of fibrosarcoma—typically arising in deep soft tissue of lower extremities and trunk—that rarely metastasizes. Clinically, low-grade fibromyxoid sarcoma is characterized by a longer survival rate compared to other sarcomas, suggesting its consideration in the differential diagnosis of cardiac tumors with a myxoid appearance.     

肢端黏液样炎性纤维母细胞肉瘤2例及文献复习

目的探讨肢端黏液样炎性纤维母细胞肉瘤的临床病理学特征及鉴别诊断。方法对2例发生在下肢末端的黏液样炎性纤维母细胞肉瘤进行光镜观察和免疫组化标记，并复习文献。结果2例发生在下肢末端的病程较长的渐进性肿块，术后局部复发。镜检：病变呈多结节状，边界不清；黏液样基质中见数量不等的各类炎细胞浸润，散在或灶性分布梭形、奇异形和多空泡状脂肪母细胞样3种形态的瘤细胞。免疫表型：肿瘤细胞Vim弥漫阳性，CD68和CD34灶性阳性，CK、SMA、HHF-35、S-100蛋白、CD45、CD45R0、CD15、CD30均阴性。结论此病病程较长，术后易局部复发，是一种低度恶性的肿瘤。鉴于病变黏液样基质及各类炎细胞浸润的背景较为突出，而特征性的瘤细胞稀疏，应注意与炎症性病变或具有相似组织形态的良性或恶性肿瘤鉴别。     

低度恶性纤维黏液样肉瘤临床病理分析

目的:探讨低度恶性纤维黏液样肉瘤(low-grade fibromyxoid sarcoma,LGFMS)的临床病理特征和诊断要点.方法:分析3例LGFMS的临床资料,观察组织学形态、免疫表型及分子病理检测结果,讨论鉴别诊断并复习相关文献.结果:患者均为女性,中位年龄57岁,肿瘤分别位于右侧膝关节前方、右侧乳腺和左侧上颌窦.肿块最大径为2.2～10.0 cm,边界欠清,似有包膜,切面灰白,部分区域呈半透明状,质中有黏液感.镜下见肿瘤组织主要由梭形纤维母细胞样细胞构成,包括两种形态区域,其一为细胞稀疏的胶原样区域;其二为细胞相对较丰富的黏液样区域.肿瘤组织中可见较多弓形血管并伴有血管周玻璃样变性.瘤细胞形态温和,无明显异型性,核分裂象罕见.免疫组织化学染色结果示:vimentin,MUC4,CD99及bcl-2阳性表达,SMA,desmin,S100,CD34,ALK及myogenin阴性表达.发生于右侧乳腺的病例行荧光原位杂交(fluorescent in situ hybridization,FISH)检测,检出FUS基因易位.发生于右侧膝关节和乳腺的2个病例分别随访20个月和51个月,患者均无瘤生存.发生于左侧上颌窦的病例于手术后12个月死亡.结论:LGFMS常见于年轻人,但各年龄段患者均可受累.好发部位为下肢近端和躯干,少见于头颈部和乳腺.LGFMS具有温和的多样性的组织学形态,容易误诊为具有黏液样结构的其他梭形细胞肿瘤.LGFMS具有转移和复发的恶性生物学行为,治疗上需对肿块作完整切除并长期随访观察.     

Hyalinizing spindle cell tumor with giant rosettes and low-grade fibromyxoid sarcoma: an immunohistochemical and ultrastructural comparative investigation

Hyalinizing spindle cell tumor with giant rosettes (HSCTGR) and low-grade fibromyxoid sarcoma (LGFMS) are 2 variants of fibrosarcoma, which share several clinicopathologic features. This study compares the light microscopic, immunohistochemical, and ultrastructural features of 2 examples of HSCTGR and 3 of LGFMS to determine the degree of overlap of these 2 tumors. HSCTGR were composed of bland spindle cells within hyalinized to myxoid stroma. Scattered throughout the lesions were characteristic rosette-like structures, formed by a central collagenous core surrounded by spindled neoplastic cells. LGFMS consisted of a mixture of fibrous and myxoid areas, composed of fibroblast-like cells arranged in a swirling, whorled growth pattern. Immunohistochemical analysis showed diffuse positivity for vimentin in all cases, while few scattered tumor cells stained for CD57, CD34, factor XIIIA, and actin. The extracellular matrix showed intense positivity for type IV collagen, laminin, and fibronectin, with the exception of myxoid areas of LGFMS and the central core of the giant rosettes in HSCTGR. Ultrastructurally, both tumor types were composed of cells with the features of fibroblasts, embedded in a collagenous stroma with irregular deposits of amorphous basal lamina-like substance. In conclusion, HSCTGR and LGFMS share similar immunophenotypic and ultrastructural features, and together with other fibrosing fibrosarcomas, like sclerosing epithelioid fibrosarcoma, may constitute a subset of fibrosarcomas formed by fibroblasts capable of producing large amounts of basal lamina-like material.     

Clinico-pathological features of breast myxoma: report of a case with histogenetic considerations

We herein report the clinical, radiological, and pathological findings of a rare case of myxoma occurring in the breast parenchyma of a 75-year-old female. The tumor was incidentally detected at a mammographic screening and, ultrasonographically, presented as an ovoid mass. Histologically, an encapsulated hypocellular, myxoid tumor with low vascularization was evident. Neoplastic cells were round- to spindle/stellate-shaped and stained with vimentin and focally with calponin. We emphasize that morphology remains preeminent in the diagnosis of a breast myxoma, while immunohistochemistry may assist in ruling out other tumor entities. Differential diagnosis with all benign and malignant myxoid lesions, primarily occurring in the breast, is provided. The histogenesis of breast myxoma is unknown. The lack of expression of desmin, α-smooth muscle actin, CD34, CD99, CD10, bcl-2 protein, and estrogen/progesterone/androgen receptors, all markers characteristically expressed by “the benign spindle cell tumors of the mammary stroma,” would suggest that breast myxoma does not fall into this tumor category and that its putative precursor mesenchymal cell resides in the interlobular stroma.     

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.     

低度恶性子宫内膜间质肉瘤临床病理分析

目的 探讨低度恶性子宫内膜问质肉瘤(LESS)的临床病理学特征、诊断和鉴别诊断。方法 分析17例LESS的临床病理特点,通过网织纤维染色、免疫组化染色和电镜观察来研究其病理学特征。结果 LESS临床上主要表现为阴道不规则流血。HE染色见肿瘤组织成巢团样浸润,肿瘤细胞圆形、卵圆形或梭形。肿瘤内有大量的小血管。网织纤维染色见网状纤维丰富,围绕瘤细胞生长。肿瘤细胞14例CD10阳性,12例ER阳性,13例PR阳性,3例actin阳性,C1934、CDll7、Melan—A肿瘤细胞均阴性。电镜观察见肿瘤细胞胞质内的中间丝呈杂乱无序的排列。结论 LESS易误诊,确诊主要依靠组织病理学和免疫组织化学;病理形态上看似良好的低度恶性子宫内膜间质肉瘤,预后不一定好。     

Myxoid solitary fibrous tumor: a study of seven cases with emphasis on differential diagnosis.

Focal myxoid change is a well-recognized feature of solitary fibrous tumor (SFT), but to date, predominantly myxoid examples of SFT have not been reported. We describe seven cases of SFT in which stromal myxoid change affected 50% or more of the tumor examined, thus obscuring typical diagnostic features. Patients ranged in age from 35 to 68 years old (median, 45 yr), with an equal sex distribution. Tumor locations included pleura, orbit, and periparotid subcutaneous tissue, as well as four cases in deep soft tissue (two in the abdominal wall and one each in the chest wall and thigh). Myxoid areas were identified grossly in four cases. Histologically, the lesions were composed of bland spindle cells disposed haphazardly or with a lacy or reticulated appearance in a myxoid, richly vascularized stroma These myxoid areas were punctuated by small cellular aggregates in four cases, and areas showing diagnostic features of SFT were present in five of seven primary excision specimens. Atypical features suggestive of malignancy were not present in any of the cases. Immunohistochemically, all of the seven cases stained positively for CD34 and CD99 (013), and all were negative for smooth muscle actin, desmin, S-100 protein, epithelial membrane antigen, and pan-keratin. There were no recurrences or metastases reported in four patients with limited follow-up (median duration, 19 mo). Recognition of this uncommon morphologic subset of SFT is important because of possible confusion, particularly in small biopsy specimens, with a variety of myxoid spindle cell neoplasms with different biologic potential. These include low-grade fibromyxoid sarcoma, myxoid synovial sarcoma, malignant peripheral nerve sheath tumor, low-grade myxofibrosarcoma, myxoid liposarcoma, myxoid spindle cell lipoma, myxoid neurofibroma, and so-called "hemangiopericytoma."     

肢端黏液炎性纤维母细胞性肉瘤

目的 探讨肢端黏液炎性纤维母细胞性肉瘤的临床病理学特征、免疫学表型及其鉴别诊断。方法 对1例发生于足背和右小腿远端的肢端黏液炎性纤维母细胞性肉瘤进行光镜观察和免疫组化标记。结果 患者因足背皮下“结节性筋膜炎”局部切除术后复发就诊。体检发现足背至右小腿远端前外侧皮下多发性结节,直径1～4cm,影像学检查提示肿瘤累及深部骨膜。镜下肿瘤由比例不等的黏液样区、透明变性区及炎症性区域混合组成。黏液样区域主要由交织条柬状排列的梭形瘤细胞组成,核显示轻至中度异型性,核分裂象罕见,间质疏松、黏液样,局部区域可见黏液湖形成。其内可见单空泡印戒样或多空泡状假脂肪母细胞,形态类似黏液纤维肉瘤。透明样区域由散在的胖梭形至卵圆形的瘤细胞和透明样间质混和组成。炎症性区域由成簇的淋巴细胞组成,与黏液样区域和透明变性区相混杂。病变内可见体积较大类似节细胞或R-S细胞的畸形细胞。免疫组化标记显示瘤细胞弥漫表达Vim,个别细胞表达p53,而CD68、actin、Des、CD34、CD30和S-100蛋白等标记均为阴性,多数淋巴细胞表达CD45RO。结论 肢端黏液炎性纤维母细胞性肉瘤是一种罕见的低度恶性软组织肉瘤,瘤细胞由变异的纤维母细胞衍化而来,熟悉其形态学特征对避免误诊为其它良性或恶性病变具有重要意义。该瘤常在局部呈侵袭性生长,具有较高的复发率,临床上应予以完整切除。     

Myxoid mixed low-grade endometrial stromal sarcoma and smooth muscle tumor of the uterus. Case report

We report the case of a 73-year-old female with myxoid mixed low-grade endometrial stromal sarcoma and smooth muscle tumor of the uterus. Grossly, the tumor sized 130 x 130 x 100 mm involved the uterine corpus almost in its entirety. Histologically, the tumor consisted of two cell types. In some areas, the tumor cells showed typical features of endometrial stromal tumors and resembled stromal cells of proliferative endometrium. In other areas, however, the tumor showed smooth muscle features and consisted of larger mostly epitheloid cells with a moderate amount of cytoplasm. In all areas, myxoid changes and multiple hyalinizing giant rosettes were present. The tumor infiltrated the myometrium in a pattern typical of low-grade endometrial stromal sarcoma. Immunohistochemically, the tumor cells showed expression of vimentin, estrogen and progesterone receptors and variable expression of CD10, α-smooth muscle actin, desmin, h-caldesmon, and cytokeratin AE1/AE3. Other markers examined including CD99, α-inhibin, cytokeratin CAM5.2, S-100 protein, and HMB45 were negative. To the best of our knowledge, mixed low-grade endometrial stromal and smooth muscle tumor with myxoid changes has not been described to date.     

Benign mesenchymal stromal tumor of the breast simulating benign schwannoma in an 81-year-old male--a case report

Presented is an unusual case of a benign mesenchymal stromal tumor of the breast in an 81-year-old male. The basic appearance of the lesion simulated benign schwannoma and was misinterpreted as a low-grade myxoid liposarcoma initially. Well-circumscribed, gray-white mass measuring 35 mm in maximum diameter was discovered deep in the parenchyma of the completely removed breast. Microscopically, the lesion consisted of myxoid, richly vascular background where dominated oval or spindle cells with impressive palisading replicating that of benign schwannoma. Rarely, the large multinucleated (floret-like type) cells were visible; no nuclear atypia or mitotic figures were found. Immunohistochemical examination confirmed expression of estrogen and progesterone receptors, antigen Bcl2 and also focal desmin positivity. Clinical examinations disclosed no objective reason for possible hyperestrinism; no other therapy followed and the patient is free of disease 19 months after operation. On the background of both detailed review and differential diagnosis of benign, so-called stromal tumor of the female breast, the rarity of this microscopic finding in male is documented.     

Malignant peripheral nerve sheath tumor with perineurial cell differentiation (malignant perineurioma)

A unique case of malignant peripheral nerve sheath tumor (MPNST) with perineurial cell differentiation occurring in a 63-year-old woman in a subcutis of the forearm is described. The tumor contained cellular and myxoid areas. The neoplastic cells were fusiform with distinct cell borders. They were arranged in storiform pattern and in wavy parallel cell cords in the cellular areas. Focally, a pleomorphism and mitotic activity (including atypical mitoses) similar to those of malignant fibrous histiocytoma were seen. The myxoid parts contained haphazardly oriented cells and scarce lipoblast-like multivacuolated cells mimicking a liposarcoma. In the differential diagnosis, myxoid liposarcoma, dermatofibrosarcoma protuberans, malignant fibrous histiocytoma and low-grade fibromyxoid sarcoma were considered. Immunohistochemically, perineurial differentiation was indicated by the diffuse expression of epithelial membrane antigen and focal reactivity for CD34. The tumor was negative with antibodies to S-100 protein, Leu-7, CD68 (KP1), vimentin and cytokeratin AE1/AE3. Ultrastructure of tumor cells revealed features of MPNST. No recurrence occurred in the patient during 2 years follow up.     

Embryonal (undifferentiated) sarcoma of the liver with peripheral angiosarcoma differentiation arising in a mesenchymal hamartoma in an adult patient

Embryonal (undifferentiated) sarcoma of the liver (ESL) is a rare malignant neoplasm composed of undifferentiated sarcomatous tissue. We are presenting a case of a 74-year-old woman diagnosed with an ESL arising from a mesenchymal hamartoma of the liver (MHL). Both lesions occur typically in childhood, with only rare reported cases in adults. Histologically, the mass consisted primarily of loose myxoid stroma admixed with bland spindle cells and extensive, cystic (lymphangioma-like) degeneration. However, also present peripherally were markedly atypical cells (including multi-nucleated forms) and hyaline globules. Additionally, atypical cells with a sinusoid tectorial growth pattern were identified, which were positive for CD31, CD34 and Factor VIII. The tumor cells of ESL are classically described as being negative for tissue-specific immunohistochemical markers. However our case demonstrated focal positivity for vascular markers CD31, CD34 and Factor VIII and this along with the sinusoidal tectorial growth pattern, mimicked an angiosarcoma.     

Renal mucinous tubular and spindle cell carcinoma: report of four cases and literature review

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K) is an unusual renal tumor. It is important to increase the recognition of the clinicopathological features of MTSCC-K and improve its clinical and differential diagnosis. This report described four cases of MTSCC-K with clinical, imaging, and pathological examination and showed that the tumor boundaries of MTSCC-K were clear, and tumor cells arranged into tubules and cord-like beams, between which was lightly stained myxoid stroma. The tumor cells were smaller and cube- or oval-shaped, with single small eosinophilic nucleoli, low-grade nuclei, and little nuclear fission. The myxoid stroma was scattered around lymphocytes and plasma cells. Immunohistochemical markers including CK7, CD117, EMA (epithelial membrane antigen), vimentin, and CK8/18, showed positive expression in tumor cells, but the tumor cells were negative for CD10 and villin. The proliferation index of Ki-67 was 5-10%. Since MTSCC-K is a rare low-grade malignancy, with unique histological and immunohistochemical characteristics, it is important for clinicians and pathologists to have a defined awareness of this tumor type in order to decrease the rate of misdiagnosis.