ABSTRACT
Merkel cell carcinoma (MCC) is a rare, highly aggressive skin cancer of neuroendocrine origin that is typically associated with either the presence of Merkel cell polyomavirus or chronic exposure to ultraviolet (UV) light. We report a case of relapsed MCC that presented with new symptoms of fatigue, back pain, and myeloid left shift identified during scheduled follow-up. The patient was found to have circulating neoplastic cells in the peripheral blood and bone marrow metastasis. Immunohistochemistry for synaptophysin, CD56, INSM-1, CK20, CD117 were positive, whereas CD34, TdT, Chromogranin, CD10, myeloperoxidase, CD3 and CD19 were negative. Flow cytometry of the peripheral blood confirmed the presence of an abnormal nonhematopoietic cell population expressing CD56 positivity. A next-generation sequencing (NGS) panel revealed the presence of variants in RB1, TP53, and other genes, some of which have not been previously described in MCC. This rare presentation highlights the challenges in the diagnosis and management of MCC.
ABSTRACT
BACKGROUND: Intravascular papillary endothelial hyperplasia (IPEH) is a benign vascular lesion that is uncommon in the central nervous system. To our knowledge, there has been only one previous report of occurrence in the pineal region. We present a second case and a review of the literature. CASE DESCRIPTION: A 28-year-old woman presented with 1 month of headaches and visual auras. Brain magnetic resonance imaging scan demonstrated a 2.6- × 1.8- × 1.3-cm nonenhancing T1-hypointense, T2-/fluid-attenuated inversion recovery-hyperintense pineal region mass with cerebral aqueduct obstruction and hydrocephalus. She underwent placement of a right extraventricular drain followed by complete surgical resection. Histologic analysis was consistent with IPEH. CONCLUSIONS: Although rare, IPEH is an entity that should be considered in the differential diagnosis for intracranial masses with radiographic features characteristic of vascular lesions. Tissue sampling is imperative for distinction from more malignant entities. Complete resection is curative and is the standard of care when feasible. Given the risk of local progression and neurologic compromise with subtotal resection of central nervous system lesions, further study regarding adjuvant treatment options is warranted.
