Solitary fibrous tumor with entrapment of minor salivary gland tissue: an unusual presentation that requires exclusion of pleomorphic adenoma.

We report two unusual cases of solitary fibrous tumor (SFT) of minor salivary glands that microscopically mimicked pleomorphic adenoma. One of these lesions presented in the retromolar region and the other in the buccal mucosa. The microscopic features of these two tumors and their intimate relationship with regional mucous minor salivary glands posed a diagnostic challenge. Awareness of the morphological diversity of SFT coupled to a judicious use of appropriate immunohistochemical probes should prove valuable to accurately segregate SFT from pleomorphic adenoma.

Incidental finding of placental choriocarcinoma after an uncomplicated term pregnancy: a case report with review of the literature.

Choriocarcinoma is frequently preceded by a complete mole, ectopic pregnancy, nonmolar intrauterine abortion, and uncommonly by a partial mole. Choriocarcinoma coexisting with or after an otherwise "normal" pregnancy is extremely rare, with an estimated occurrence of 1 per 160,000 pregnancies. We here report a case of a placental choriocarcinoma with no metastases in a full-term intrauterine pregnancy. The patient is a 29-year-old gravida 2 para 1 female, who had an uncomplicated full-term vaginal delivery of a healthy 3030 g female infant. Her current pregnancy was uneventful, and past medical history was significant for an elective termination of pregnancy 2 years ago at 8 weeks of gestation. Routine examination of the placenta showed a gray-tan nodule, measuring 2 cm in the largest dimension, with a papillary cut surface. Microscopically, this nodule was composed of highly atypical cytotrophoblastic cells and multinucleated atypical syncytiotrophoblastic cells, which were positive for beta-human chorionic gonadotrophin by immunostaining. Extensive necrosis and multiple foci of hemorrhage were present. The overall morphologic and immunohistochemical features were diagnostic for choriocarcinoma. Further investigations, including a full body computed tomography scan, showed no lesions suspicious for metastases. The patient is currently asymptomatic and being followed-up with monthly beta-human chorionic gonadotrophin levels, the most recent one being negative. By reporting this case and reviewing the literature, we support the opinion of a recent similar case report that the incidence of placental choriocarcinoma may actually be higher than expected, as placental examination after a normal spontaneous delivery is not routinely performed at most of the institutions.

Giant clear cell hidradenoma of the knee.

Hidradenomas, also referred to as nodular hidradenomas or clear cell hidradenomas (CCH), are benign cutaneous eccrine tumors usually 2-3 cm in dimension. Hidradenomas are relatively common; however, giant forms are rare. We report a case of an 8.0 x 6.0 x 3.0 cm clear cell hidradenoma of the left knee in a 43-year-old man. The tumor was mobile, located above the patellar tendon and was without bony involvement on imaging studies. Grossly, the resected tumor was unencapsulated and tan, with a solid and cystic cut surface showing papillary excrescences on the cyst wall. Microscopically, the tumor cells showed an infiltrative growth pattern at the periphery, however, the tumor cytology was bland and no necrosis or mitoses were identified. The overlying dermis contained hemosiderin pigment deposition and infiltration with eosinophils. Immunohistochemically, tumor cells were positive for cytokeratin, CAM5.2, p53, carcino-embryonic antigen (CEA) and epithelial membrane antigen (EMA), and negative for CD10 and Ki-67. The cytological features of hidradenomas can present diagnostic challenges, as other 'clear cell' tumors such as metastatic renal cell carcinoma should be considered. Immunohistochemical studies and differential diagnoses are discussed.

Platelet-derived growth factor enhancement of two alloplastic bone matrices.

BACKGROUND: The use of alloplastic matrices that mimic the mineral phase of bone has become a viable alternative to current mainstream therapies in dentistry such as allografts and autogenous grafts. Because alloplastic bone substitutes generally have relatively poor osteogenic properties, analyzing their potential as vehicles to deliver growth factors is an important step in assessing methods to enhance their clinical efficacy. The aim of these studies was to treat beta-tricalcium phosphate (beta-TCP) and calcium sulfate (CaSO(4)) with platelet-derived growth factor (PDGF)-BB to enhance the osteogenic capabilities of these materials. METHODS: In the beta-TCP studies, PDGF-BB adsorption and release were accomplished using (125)I radiolabeled growth factor and non-radioactive human recombinant PDGF at a ratio of 1:300 M. For the adsorption studies, the radiolabeled PDGF-BB/ non-radioactive PDGF solutions with resultant PDGF concentrations of 10(7) and 10(8) M were incubated with beta-TCP from 1 to 120 minutes, and the amount of adsorbed (125)I-PDGF-BB was measured using a gamma counter. Similar adsorption studies were conducted with a 30-minute incubation of beta-TCP with various PDGF concentrations. In vitro release studies were conducted with beta-TCP to which radiolabeled PDGF had been adsorbed as above. Release studies were also conducted with CaSO(4) that was hydrated with the radioactive PDGF solution described above for the TCP studies. In vivo PDGF-BB release from beta-TCP and CaSO(4) was evaluated in a mouse model, where the radioactive PDGF/non-radioactive PDGF-BB treated beta-TCP or CaSO(4) sample was inserted subcutaneously and later removed for radioactive measurement. Proliferation of human osteoblastic cells in the presence of PDGF- treated beta-TCP or CaSO(4) was assessed by (3)H thymidine incorporation. RESULTS: The absorption studies revealed that PDGF-BB was absorbed in a concentration and time-dependent manner to beta-TCP. In the in vitro release studies, approximately 45% of the adsorbed PDGF-BB was released after 10 days. In vivo release from both materials occurred faster than in vitro release. Osteoblastic cells incubated with PDGF-BB-treated matrices showed significantly (P <0.05, ANOVA) greater proliferation than with control matrices alone. CONCLUSION: These experiments demonstrate the feasibility of using PDGF-BB in combination with alloplastic materials such as beta-TCP or CaSO(4) to serve as more effective bone graft materials with enhanced osteogenic properties.