Primary pineal tumors - Unraveling histological challenges and certain clinical myths.

BACKGROUND: Pineal gland tumors range from the well-differentiated "pineocytoma" [World Health Organization (WHO) grade I], which have a very good prognosis, to the aggressive and poorly differentiated "pineoblastoma" (WHO grade IV) with "pineal parenchymal tumor of intermediate differentiation" (PPTID; WHO grades II and III) occupying intermediary differentiation and prognosis. Papillary tumor of the pineal region (PTPR; WHO grades II and III) is a distinct entity with propensity for recurrence and spinal dissemination. However, the diagnostic criteria to differentiate these entities, especially between WHO grades II and III of both PPTID and PTPR, remain nebulous. OBJECTIVE: To evaluate the relative frequency of the individual entities and histomorphological (including the proliferation indices) features across the spectrum of pineal parenchymal tumors (PPTs) [including PTPRs] along their course. DESIGN: All cases of PPTs were retrieved, reviewed, and graded based on the histological criteria defined in the literature. RESULTS: PPTID, more commonly seen in young adults, was the most common subtype of PPT. This was followed by pineoblastoma which was more commonly seen in children. Clinical progression was seen in both grades II and III of PPTID; however, it was more commonly seen in cases with a MIB1 labeling index of >10%. PTPRs (both grades II and III) showed an aggressive histological transformation and also intraparenchymal metastasis. CONCLUSION: PPTIDs are the most common adult primary PPTs and have the potential to progress and disseminate in both grades II and III. Both grades of PTPRs have a metastatic potential. These findings suggest the need for postoperative adjuvant therapy in both grades of PPTID and PTPR.

Unsuspected Metastases to Muscles in Osteosarcoma Detected on 18F-Sodium Fluoride PET-CT.

Metastasis of osteosarcoma to the muscles is extremely rare. F-sodium fluoride (NaF) is a bone-seeking agent that can also localize extraosseous calcifying lesions. We report the case of a 33-year-old woman with osteosarcoma of the right fibula treated with surgery and chemotherapy 2 years back who was referred for F-NaF PET-CT to evaluate possible metastatic lesions. F-NaF PET-CT unexpectedly detected 2 foci of soft tissue increased tracer uptake in the right lateral abdominal and left paraspinal muscles, which corresponded to the focal calcification in the muscles. The pathological examination revealed metastatic osteosarcoma to the muscles.

Ossifying Fibromyxoid Tumor: An Update.

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm of uncertain differentiation, initially described by Enzinger and colleagues. Until now, nearly 300 such cases have been reported worldwide. The histogenesis of these tumors remains controversial. These tumors show characteristic imaging findings and exhibit a spectrum of histopathologic features, including classical and atypical subtypes. Local recurrences and, occasionally, distant metastases have also been reported. A complete tumor resection forms the preferred treatment modality for these tumors, along with follow-up, as these tumors have an uncertain malignant potential. Lately, certain "molecular signatures" underlying OFMTs have been described that can further aid in reaching an accurate diagnosis for these tumors and unraveling their pathogenesis. This article is a review of the clinical, radiologic, histopathologic, and molecular features of OFMTs.