ABSTRACT
Prostatic yolk sac tumour is a germ cell tumour with a wide range of age of occurrence, unusual anatomic locations, diverse morphologic patterns, and aggressive biologic behavior, posing challenges both to diagnosis and clinical management. We report a rare case of primary yolk sac tumour of the prostate with extensive local and liver metastasis, the latter of which exhibited sheets of small blue cells expressing CD99 and focal sall4 on biopsy. Positivity for CD99 and gata3 in the initial biopsy raised the differential diagnosis of Ewing sarcoma and poorly differentiated carcinoma. The primary tumour demonstrated an admixture of solid and glandular growth patterns and occasional Schiller-Duval bodies. A panel of immunohistochemical stains showing positivity for AE1/3, sall4, cdx2, and focal alpha-fetoprotein, and negativity for oct-4, facilitated the diagnosis. A thorough review of the literature and our current report indicate that a large tumour load, incomplete tumour resection, limited response to preoperative neoadjuvant chemotherapy, and late stage of the disease are predictive factors for a poor clinical outcome.
Subject(s)
Endodermal Sinus Tumor , Liver Neoplasms , Neoplasms, Germ Cell and Embryonal , Prostatic Neoplasms , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Endodermal Sinus Tumor/blood , Endodermal Sinus Tumor/diagnostic imaging , Endodermal Sinus Tumor/pathology , Endodermal Sinus Tumor/therapy , Fatal Outcome , Humans , Liver Neoplasms/blood , Liver Neoplasms/diagnosis , Liver Neoplasms/secondary , Liver Neoplasms/therapy , Male , Neoadjuvant Therapy , Neoplasms, Germ Cell and Embryonal/blood , Neoplasms, Germ Cell and Embryonal/diagnostic imaging , Neoplasms, Germ Cell and Embryonal/pathology , Neoplasms, Germ Cell and Embryonal/therapy , Prostatic Neoplasms/blood , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/pathology , Prostatic Neoplasms/therapy , Stem Cell Transplantation , Tomography, X-Ray Computed , alpha-Fetoproteins/analysisABSTRACT
The unique properties of eukaryotic DNA modified via methylation of cytosine residues are believed to result from the action of a conserved family of proteins, the MBD family. The prototype member of this family, MeCP2, was isolated independently in two laboratories. One group isolated MeCP2 as a methylated DNA-binding protein, the second as a sequence-specific DNA-binding protein. Multiple lines of evidence suggest that MeCP2 functions in assembly of specialized chromatin architecture. While initial findings pointed to an enzymatic mechanism involving histone modification for transcriptional repression mediated by MeCP2, emerging studies clearly provide exceptions to this model. In a recent study, highly compacted, unique chromatin structures were generated by stoichiometric binding of MeCP2 to model chromatin fibers. These findings support the likelihood that MeCP2 can utilize two independent, but not mutually exclusive, mechanisms to repress transcription: enzymatic and structural mechanisms.
