Prominent Myxoid Stroma Research Articles

Clear CelI HepatocelIular Caxinoma with Abundant Myxoid Stroma

A case of the clear cell variant of hepatocellular carcinoma with an abundant myxoid stroma is presented. The tumor occurred in a 55-year-old Japanese man, and swelling of the scrotum was the initial symptom. The patient underwent high-level orchiectomy, and the pathologic diagnosis was a metastatic tumor on the surface of the processus vaginalis and intact testis. Extensive examination failed to show a primary site. Subsequent autopsy revealed a large hepatic tumor and metastatic nodules with a prominent myxoid appearance in multiple organs. Histologically, each tumor consisted of uniform small tumor cells with clear cytoplasm attributed to abundant accumulation of glycogen particles, and an abundant myxoid stroma was also present. The tumor cells were positive for keratin, alpha 1-antitrypsin, alpha 1-antichymotrypsin, liver ferritin, prealbumin, and fibrinogen, but lacked alpha-fetoprotein. These findings indicated that this case was hepatocellular carcinoma of the clear cell type with a prominent myxoid stroma.

Atypical Decubital Fibroplasia

We report 28 cases of atypical decubital fibroplasia, a distinctive pseudosarcomatous fibroblastic proliferation occurring primarily but not exclusively in physically debilitated or immobilized patients. The subjects included 16 women and 12 men ranging in age from 15 to 95 years. Peak incidence was in the 8th and 9th decades of life. Anatomic locations included the soft tissues overlying the shoulder (eight cases), posterior chest wall (five cases), sacrum (five cases), greater trochanter (four cases), buttock (two cases), thigh (two cases), and arm (two cases). Symptoms were due to a painless mass of 3 weeks' to 6 months' duration. Most lesions were ill-defined, focally myxoid masses that ranged from 1 to 8 cm. Histologically, they were situated in the deep subcutis and secondarily involved adjacent skeletal muscle (11 cases) and tendon (three cases). Extensive epidermal ulceration was typically absent. Microscopically, the lesions had a lobular configuration. They were characterized by zones of fibrinoid necrosis and a prominent myxoid stroma rimmed by ingrowing, ectatic, thin-walled vascular channels. All cases contained atypical, enlarged, degenerated fibroblasts with abundant basophilic cytoplasm, large hyperchromatic, smudged nuclei, and prominent nucleoli; these features resulted in a superficial resemblance to proliferative fasciitis. The enlarged, atypical fibroblasts stained diffusely and strongly for vimentin (15 of 15 cases) and focally for muscle-specific actin (10 of 15 cases), keratin (one of 15 cases), CD68 (10 of 15 cases), and CD34 (five of nine cases) antigens; none of the cases stained for desmin. A malignant diagnosis was considered in 43% of cases. Follow-up in 21 patients ranged from 2 to 78 months (median, 12 months). Two lesions recurred once, one recurred twice, and none metastasized; no deaths were attributable to the lesions. The clinical, histologic, and immunohistochemical features of atypical decubital fibroplasia indicate it is a unique type of pressure sore displaying degenerative and regenerative features distinct from decubitus ulcer. Its recognition by pathologists and clinicians in elderly and debilitated patients is important to avoid misdiagnosis as a sarcoma and to prevent or minimize the occurrence of decubital fibroplasia in progressively aging patient populations.

Myxoid Variant of Epithelioid Leiomyosarcoma of the Uterus

A rare case of myxoid variant of epithelioid leiomyosarcoma of the uterus in a 76-year-old woman is reported. Palpation and computed tomography revealed an enlarged uterus. Total hysterectomy and bilateral salpingo-oophorectomy were performed, and a hemispheric tumor, measuring 2.7 x 2.5 x 1.8 cm, was found protruding into the uterine cavity of the upper uterine segment. The tumor contained a prominent myxoid stroma and epithelioid tumor cells, which were round and polygonal in shape and showed positive immunoreactivity for desmin and vimentin. High mitotic activity was observed in the tumor cells. Electron microscopic examination revealed bundles of filaments in the cytoplasm and fine reticular material in the extracellular matrix. Histochemically, the myxoid stroma contained abundant acid mucopolysaccharide. The tumor cells were considered to originate from smooth muscle cells, while the myxoid stroma expressed varying differentiation of uterine mesenchymal cells. The patient is currently well with no evidence of recurrence or metastasis one year after the operation.

Squamous cell carcinoma with prominent myxoid stroma

Three cases of a squamous cell carcinoma with a prominent myxoid stroma are reported. One case in a 70-year-old woman had presented as a lump in the breast, the other two presented as polypoid lesions of the larynx and cervix uteri in a 65-year-old man and 61-year-old woman, respectively. The carcinomatous component was immersed in abundant extracellular mucosubstances. In addition to occasional squamous pearls, it displayed immunocytochemical evidence of high-weight keratin present in the neoplastic cells and, in one case, desmosomal attachment under electron microscopy. The extracellular mucosubstances proved to be similar to those seen in connective tissue. The differential diagnosis with histologically similar lesions has been taken into consideration, and it has been suggested that this newly described entity showing abundant myxoid stroma has to be distinguished from numerous benign and malignant myxoid soft tissue tumors.

Morphologic Diversity in Malignant Melanomas

A review was conducted of 335 malignant melanomas to identify variant morphologic patterns that might be confused with other tumors. In all, 27 predominantly amelanotic neoplasms with unusual histologic features were selected for additional study. These included nine with an adenoid or pseudopapillary pattern, seven small cell neoplasms, five with prominent myxoid stroma, four with a hemangiopericytoma-like appearance, and two composed of neoplastic cells with a signet-ring configuration. A diagnosis of melanoma was confirmed in all cases by Fontana-Masson strains for melanin pigment, electron microscopic examination, or the results of immunohistochemical analyses for cytokeratin, vimentin, S-100 protein, and the HMB-45 antigen. One tumor was associated with a congenital hairy melanocytic nevus, five were vulvovaginal lesions, four arose in the sinonasal tract, and one occurred in the rectum. Four of the specified microscopic patterns were observed in both primary and secondary neoplasms; the two signet-ring cell melanomas were recurrent lesions. The authors conclude that malignant melanomas may assume the histologic guise of adenocarcinomas, small cell carcinomas, and sarcomas, in a variety of tissue sites. Special studies designed to detect melanocytic differentiation are therefore appropriate in diverse differential diagnostic settings.

Malignant schwannoma associated with von Recklinghausen's neurofibromatosis

A series of 46 malignant schwannomas occurring in soft parts of patients having von Recklinghausen's neurofibromatosis was analyzed. The diagnosis of malignant schwannoma was based upon the occurrence of malignant spindled cells closely resembling Schwann cells in the neoplasm and the close association or origin of the malignant schwannoma in a neurofibroma (27 tumors), or a large peripheral nerve (31 tumors). Additional histologic features useful in making the diagnosis of malignant schwannoma included the arrangement of the spindled tumor cells in a whorled pattern about thin-walled, gaping blood vessels, perivascular cellular proliferation and the presence of prominent myxoid stroma containing abundant hyaluronidase-sensitive acid mucopolysaccharides. Nuclear palisading was present in only one case. Eight tumors containing both neoplastic Schwann cells and rhabdomyoblasts and five containing both neoplastic Schwann cells and rhabdomyoblasts (malignant "Triton" tumors) and five containing foci of malignant cartilage cells were included in the series. The neoplasms occurred principally in adults (median age, 34 years) and were most common in the lower extremity (18 cases) and retroperitoneum (11 cases). A mass with or without pain was the most common presenting symptom (28 cases). The median size of excised tumors was 11 cm. The malignant schwannomas were highly malignant neoplasms, causing the death of 39 patients within five years and two patients within 6--10 years after diagnosis. Only four patients were alive and free of tumor 5--15 years after diagnosis.