PLAG1 Immunohistochemical Staining Is a Surrogate Marker for PLAG1 Fusions in Lipoblastomas.

BACKGROUND: The hallmark of lipoblastoma is a PLAG1 fusion. PLAG1 protein overexpression has been reported in sporadic PLAG1-rearranged lipoblastomas. METHODS: We evaluated the utility of PLAG1 immunohistochemical staining (IHC) in 34 pediatric lipomatous tumors, correlating the results with histology and conventional cytogenetics, FISH and/or next generation sequencing (NGS) results. RESULTS: The study included 24 lipoblastomas, divided into 2 groups designated as "Lipoblastoma 1" with both lipoblastoma histology and PLAG1 rearrangement (n = 16) and "Lipoblastoma 2" with lipoblastoma histology but without PLAG1 cytogenetic rearrangement (n = 8), and 10 lipomas with neither lipoblastoma histology nor a PLAG1 rearrangement. Using the presence of a fusion as the "gold standard" for diagnosing lipoblastoma (Lipoblastoma 1), the sensitivity of PLAG1 IHC was 94%. Using histologic features alone (Lipoblastoma 1 + 2), the sensitivity was 96%. Specificity, as defined by the ability to distinguish lipoma from lipoblastoma, was 100%, as there were no false positives in the lipoma group. CONCLUSIONS: Cytogenetics/molecular testing is expensive and may not be ideal for detecting PLAG1 fusions because PLAG1 fusions are often cytogenetically cryptic and NGS panels may not include all partner genes. PLAG1 IHC is an inexpensive surrogate marker of PLAG1 fusions and may be useful in distinguishing lipoblastomas from lipomas.

"Blooming too soon": A case of precocious puberty / Philippine Journal of Obstetrics and Gynecology

Precocious puberty is the onset of pubertal development at an earlier age than is expected based upon established normal standards. The cause of precocious puberty may range from a variant of normal development (eg. premature adrenarche or isolated premature thelarche) to pathologic conditions with significant risk of morbidity and even death (eg. malignant germ-cell tumor or astrocytoma). A case of an 18 month old female presenting with vaginal bleeding following a previously noted breast enlargement was described. Initial assessment based on the patient's history and physical examination is suggestive of precocious puberty. Hormonal studies indicated normal levels of FSH and LH, with an elevation in estradiol. Radiographic analysis showed a normal bone age. Cranial MRI revealed no abnormal masses. Sonographic evaluation showed bilateral cystic masses in the ovaries. A diagnosis of peripheral precocious puberty associated with functional ovarian cysts was made, and the patient was monitored for progression of pubertal development.