Characterization of myxoid substance of human aortic sarcoma

An autopsy case of aortic sarcoma which was located in the intima of the abdominal aorta and characterized by abundant extracellular myxoid substances was examined. Histological, immunohistochemical and ultrastructural studies revealed no characteristics suggestive of endothelial, leiomyogenic or histiocytic differentiation. Histochemical and biochemical analyses revealed that the myxoid substances were glycosaminoglycans (GAGs) consisting of hyaluronic acid (85% of the total GAG) and chondroitin sulfate proteoglycan (15% of the total GAG). Neither heparan sulfate proteoglycan nor dermatan sulfate proteoglycan was detected. In the aorta, GAGs are synthesized mainly by arterial smooth muscle cells and endothelial cells. Among these cells, the arterial smooth muscle cell is the principal cell type that synthesizes aortic GAGs, predominantly chondroitin sulfate proteoglycan, whereas the endothelial cell synthesizes small amounts of GAGs, predominantly heparan sulfate proteoglycan. Therefore, the results of this study suggest that the tumor cells of the present case have a property similar to arterial smooth muscle cells in terms of GAG synthesis, and that the tumor originated most probably from arterial smooth muscle cells.     

Vulvar hibernoma

A 35 year old woman presented with 18 months history of a painless, soft, well-circumscribed, vulvar subcutaneous lump which measured approximately 7 cm. The lesion was completely excised and microscopically was consistent with a hibernoma. According to the available literature in English, this is the first reported case of hibernoma of the vulva.     

Myxoid mesenchymal tumors of uterus: endometrial stromal and smooth muscle tumors, myxoid variant

Four myxoid variant of uterine mesenchymal tumors are reported. One was a low grade stromal sarcoma with infiltrative margins and the others were well circumscribed tumors corresponding to an endometrial stromal nodule and two leiomyomas. They were hypocellular neoplasms composed of stellated cells with an abundant Alcian Blue positive myxoid matrix. The myxoid nature of the neoplasms obscured their cellular nature and made the distinction between smooth muscle and endometrial stromal tumors difficult. Endometrial stromal tumors, showed very focal areas of small basophilic cells, characteristic of endometrial stroma. The diagnosis was based on the presence of a spiral arteriolar network, a CD10 positivity as well as the absence of h-caldesmon and desmin expression. The two myxoid leiomyomas showed more spindle cells and a desmin expression while h-caldesmon was negative and CD10 focally positive in both cases. Myxoid variant of endometrial stromal tumors does not necessarily exhibit the typical morphology of endometrial stroma. They may demonstrate morphological features of smooth muscle tumors in the uterus. Also, myxoid changes in uterin smooth muscle tumors may modify the classical immunoreactivity of smooth muscle markers in these tumors and make it difficult to distinguish between benign and malignant neoplasms. An immunohistochemical panel of antibodies including CD10, h-caldesmon and desmin may help in establishing the correct diagnosis.     

Cytodiagnosis of hibernoma: a case report

Cytologic examination of material obtained by fine-needle aspiration of a supraclavicular mass revealed features that were consistent with a hibernoma. Subsequent histologic study following resection of the mass confirmed the cytologic impression. The clinical, histologic, and cytologic features of this rare tumor along with the differential diagnosis and pitfalls in the cytologic diagnosis are discussed in this article.     

Diagnostic pitfalls associated with fine-needle aspiration biopsy in a patient with the myxoid variant of monophasic fibrous synovial sarcoma

Synovial sarcoma (SS) is one of the most common soft tissue tumors that typically presents in the extremities of young adults, but may occur at any site and affect children during the first decade. Herein we discuss a 12-yr-old male who complained of left foot pain and plantar mass. A fine-needle aspiration biopsy of an 8 cm subcutaneous mass was performed revealing a myxoid spindle cell neoplasm. The cytologic differential diagnosis included a myxoid neurofibroma, neurothekeoma, and a myxoid sarcoma. Subsequent excision of the mass revealed a monophasic fibrous SS with myxoid features. Examination of the tissue by fluorescence in situ hybridization confirmed the presence of characteristic SS SYT gene rearrangement at chromosome 18q11.2. This case underscores that the cytologic distinction of mxyoid spindle cell tumors may be challenging. We report the cytologic features of a myxoid monophasic fibrous SS, and discuss its distinction from other benign and malignant myxoid soft tissue neoplasms.     

Endocrine activity in a large hibernoma

Light, ultrastructural, biochemical and histochemical analyses of a large hibernoma revealed endocrine-like secretory activity. By biochemical and gas chromatographic analyses, cholesterol and steroid hormones were detected. These findings were confirmed by detection of cortisol and testosterone, radioimmune assay, and immunocytochemical testing. Morphologic evidence of endocrine-like secretory activity was provided by both transmission and scanning electron microscopic examination, which, in addition, revealed unusual features that have not previously been described for hibernomas: 1) "endoplasmacrine" lipid granule secretion, 2) rows of pedunculated or detached plasmalemmal granules in perisinusoidal cells, 3) periodic plasmalemmal densities, which were present also along membrane remnants surrounding lipid granules, and 4) highly innervated interstitial veins with eccentric lumens and peculiar thick muscular coats, which resembled structures seen in humans only in the central vein of the adrenal gland.     

Dendritic fibromyxolipoma: A variant of spindle cell lipoma with extensive myxoid change,with cytogenetic evidence

Dendritic fibromyxolipoma (DFML), a rare, recently described distinct benign soft tissue tumor, has many clinicopathological features reminiscent of spindle cell lipoma and solitary fibrous tumor with myxoid change. It is distinguished histologically from both entities by the presence of spindle and stellate cells with dendritic cytoplasmic prolongations, prominent myxoid stroma with abundant keloidal collagen and occasional small plexiform vascular proliferation. We describe a case of histologically confirmed DFML of the left shoulder in a 67‐year‐old male, in which subsequent cytogenetic analysis revealed deletion involving 13q14.3 region in all the tumor cells, typically detected in spindle cell lipoma. In the presence of many clinicopathological similarities between DFML and spindle cell lipoma including chromosomal abnormalities, we postulate that DFML is merely a rare variant of spindle cell lipoma with extensive myxoid degeneration, and may not be considered as a separate entity. The possible differential diagnosis and their distinguishing features are briefly discussed.     

心包原发性黏液型脂肪肉瘤一例

患者男,24岁,右脑隐痛4年,加剧4d,于1997年7月14日入院。患者自1994年起右胸隐痛,活动后尤甚,入院前4d疼痛加剧,不得不下蹲以图缓解,疼痛呈持续性向右肋及右肩背处放射,     

Poorly differentiated extraskeletal myxoid chondrosarcoma with t(9;22)(q22;q11) translocation presenting initially as a solid variant devoid of myxoid areas

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue tumor associated with the translocation t(9;22)(q22;q11-12). Although it has a typical microscopic appearance its morphologic spectrum is wide. We report a case of clinically aggressive, poorly differentiated EMC showing the characteristic translocation, which presented initially as a poorly differentiated sarcoma devoid of myxoid areas in the upper arm of an 85-year-old man. The recurrent tumor contained scattered myxoid areas, which merged imperceptibly with the poorly differentiated areas. Some myxoid areas contained necrotic foci surrounded by viable cells giving rise to a pseudorosette-like arrangement. There were epithelioid foci. This case confirms that solid variants of EMC may exist. Poorly differentiated EMC may have a worse prognosis than classic EMC.     

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.     

Pulmonary myxoid leiomyosarcoma

A primary myxoid leiomyosarcoma arising from the peripheral bronchus of the right middle lobe was removed from a 20 year old man and examined by immunohistochemistry and electron microscopy. The tumor was well circumscribed, yellow-whitish focal polypoid growth into the bronchial lumen and consisted of spindle cells with abundant myxoid substance in the stroma. Intrapulmonary metastasis, invasion to the bronchial wall and a few mitotic figures were found. Immunohistochemically, several, but not all, tumor cells were positive against anti-vimentin, anti-S-100 protein, anti-myosin and anti-muscle specific actin. Ultrastructurally, tumor cells had thin filaments with dense bodies, pinocytic vesicles and discontinuous basal lamina. These findings indicate a myoxoid variant of leiomyosarcoma arising from mesenchyme in the peribronchial area.     

Pure hibernoma of the breast: insights about its origins

Hibernomas are rare benign tumors composed of cells reminiscent of brown adipose tissue. In the mammary gland, hibernomas are extraordinary rare, with only 4 cases reported previously. We report the fifth case in a 37-year-old woman who presented with a slowly growing mobile mass in her right breast. A 2.2 cm well-circumscribed lobulated mass was completely removed. The histopathologic analysis showed the full characteristics of the hibernoma. A review of the clinicopathologic features of hibernomas, its relation to brown adipose tissue in humans, and considerations about its histogenesis are made.     

Retrovesical myxoid leiomyosarcoma

An elderly man with a retrovesical leiomyosarcoma is described. This unusual tumor showed a prominent myxoid stroma. The smooth muscle origin of the malignant spindle cells was confirmed by ultrastructural study. Review of the literature has not yielded a similar case.     

Mediastinal hibernoma: a case report

Hibernomas are rare benign tumours that arise most often in adults from the remnants of fetal brown adipose tissue. They usually affect muscle and subcutaneous tissue and are asymptomatic and slow growing. The distribution of this tumour follows the sites of persistence of brown fat. Out of more then 100 cases described in the word literature only three hybernomas were mediastinal. A recent clinicopathological study of 170 cases from the Armed Forces Institute of Pathology confirmed the exceptionality of the intrathoracic location. This report describes a very rare case of mediastinal hibernoma in a young man.