Rhabdomyosarcoma With Diffuse Bone Marrow Metastases

Isolated Pancreatic Metastasis in a Patient With Orbital Rhabdomyosarcoma: A Report of a Rare Case

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents and its occurrence in adults is extremely rare. There are three major subtypes of RMS of which alveolar RMS (ARMS) has the worst prognosis and tends to metastasize to unusual locations such as the pancreas. We present a case of a 19-year-old male with a rapidly enlarging right orbital mass, the imaging of which revealed it to be an infiltrative lesion with extension into the nasal cavity, ethmoid sinuses, and intracranial involvement. Histopathology confirmed the diagnosis of ARMS. A staging CT scan showed an enlarged and hypoenhancing pancreas; the histopathology test confirmed ARMS metastasis. It is important to consider pancreatic involvement in patients with ARMS, as it may be misinterpreted with other pathologies such as pancreatitis and pancreatic lymphoma. Metastasis to the pancreas can significantly alter the clinical approach and staging, underscoring the need for accurate diagnosis and staging in these patients.

18F-FDG PET/CT findings of paratesticular alveolar rhabdomyosarcoma

Rhabdomyosarcoma (RMS) originates from primitive mesenchymal cells and is the most common soft tissue tumor in childhood. 18F-fluoro-deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) has been reported to be valuable in RMS staging and risk stratification. Paratesticular RMS is a relatively uncommon form of RMS, most of which are of the embryonal histologic type. Paratesticular alveolar RMS is associated with aggressive behavior, high metastatic potential, and poor outcomes. To the best of our knowledge, 18F-FDG PET/CT imaging findings of paratesticular alveolar RMS have never been described. Here, we report on a 16-year-old boy's rare paratesticular alveolar RMS with multiple metastases and its findings on 18F-FDG PET/CT. This case also demonstrates the potential value of 18F-FDG PET/CT in RMS staging and treatment decisions, and may aid in the differential diagnosis.

Cytomorphological evaluation of non-haematopoietic malignancies metastasizing to the bone marrow

Bone marrow (BM) is one of the rare but important site of metastasis of solid tumors. The key steps of metastasis include invasion, intravasation, circulation, extravasation, and colonization. Tumor cells may express some adhesion molecules that promote the transmigration to the marrow space and link them to the marrow stroma with subsequent engraftment. It is important to detect the bone marrow metastasis for initial clinical staging, therapeutic selection, prognostic risk stratification, assessment of response to therapy and predicting relapse. Prognosis of non-hematopoietic malignancies with BM metastasis is dismal. Due to occulting and atypical clinical manifestations, bone marrow metastases can be easily missed or misdiagnosed, leading to higher mortality rates. The important factors on which the prognosis of patients with bone marrow metastases depends are primary tumor site, performance status, platelet count, and therapeutic regimens (systemic chemotherapy or palliative/supportive care). Further, in cases with BM metastasis with unknown primary sites, misdiagnosis can lead to delayed initiation of therapy and increased mortality. BM metastasis is seen in less than 10% of patients with metastatic cancer and is common in lung, breast or prostate carcinoma. Bone marrow metastasis can be presented as the initial presentation with hematological changes and may be misdiagnosed as a primary haematopoietic disorder. Leucoerythoblastic blood picture is the most common peripheral blood smear finding indicating BM metastasis, may be an indicator of associated BM fibrosis. Bone marrow aspiration and biopsy with immunohistochemistry (IHC) is an easy, cost effective and gold standard method of detection of BM metastasis. BM biopsy is superior to bone marrow aspirate for detection of metastasis. Morphology of metastatic cells is as per the primary site of tumor. Immunohistochemistry is a useful adjunct to morphology in reaching a definitive diagnosis even in case with carcinoma unknown primary (CUP) and also in diagnosing case of unsuspected malignancies. Though bone marrow is not among the most common site of involvement in CUP, which are liver, bone, lymph nodes and lung. But BM, if involved, the site of origin is determined using the immunohistochemistry panel applied to the metastatic deposits based on the morphology The aim of the review is to discuss the hematological findings of non-haematopoietic malignancies metastasizing to the bone marrow, emphasizing on histomorphology with IHC and its significance in establishing primary diagnosis in clinically unsuspected cases.