Methylation profiling of mesothelioma using real-time methylation-specific PCR: a pilot study.

We tested whether methylation profiles generated by real-time methylation-specific PCR (MSP) can be useful in differentiating benign, reactive mesothelial cell proliferation (RM) from malignant mesothelioma (MM). Forty-two of the 63 cases (67%) yielded informative results for RARbeta2, GPC3, CDKN2A (p16), TERT, and CCND2 (cyclinD2) gene methylation. DNA methylation of any gene was observed in much higher frequency in MM cases than RM cases (63% vs. 33%, P < 0.05). Individual gene methylation was higher in the MM than the RM cases for most of the genes; however, this was not statistically significant (RARbeta2: 58% vs. 33%, P > 0.05; GPC3: 36% vs. 27%, P > 0.05; CDKN2A: 4% vs. 0%; TERT: 4% vs. 0%), while CCND2 methylation was not detected in any case. Although preliminary, we demonstrate that real-time MSP can be applied to archival specimens and gene methylation profiling may have potential to be a useful ancillary tool to help distinguish MM from RM.

Fine-needle aspiration of spinal osteoblastoma in a patient with lymphangiomatosis.

Diagnosis of osteoblastoma by fine-needle aspiration (FNA) is rare, as in most patients, excisional biopsy is performed. We report a case of FNA diagnosis of a spinal osteoblastoma in a lymphangiomatosis patient. The patient had a history of lymphangiomatosis since birth with lymphangiomas removed from various locations, and had radiograph evidence of multifocal vertebral involvement. He presented with an enlarging C3 posterior element vertebral lesion. Clinically and radiologically, it was suspicious for lymphangiomatosis involvement. A computed tomography (CT)-guided FNA yielded a moderately cellular specimen. Lesional cells exhibited plasmacytoid features, fine chromatin, smooth nuclear membranes, and binucleation, in a background of occasional osteoclastic cells, spindle cells, and osteoid matrix. A cytological diagnosis of osteoblastoma was favored and confirmed with follow-up surgical biopsy. We believe that this is the first case reporting an osteoblastoma diagnosed by FNA in a lymphangiomatosis patient. We describe the clinical and cytological findings of osteoblastoma and its differential diagnosis.