ABSTRACT
Acute promyelocytic leukemia (APL) is identified as the M3 subtype of acute myeloid leukemia (AML). APL is presently one of the most curable leukemias. We describe here a rare case of APL who presented as a relapsed disease after 1 year of chemotherapy for AML. The patient lacked t(15;17) at the initial presentation but was present later at the time of relapse. The patient attained a complete remission following treatment with all-trans retinoic acid (ATRA) and arsenic trioxide-based therapy. We discuss the possible mechanism behind secondary acquisition of promyelocytic leukemia/retinoic acid receptor alpha (PML-RARA) at relapse of AML. We also briefly discuss the clinical features, diagnosis and treatment of APL.
ABSTRACT
OBJECTIVE: To describe a unique case of a metastatic thymic carcinoma to the hyperplastic parathyroid gland and to present a challenging management dilemma. METHODS: Our patient is 60-year-old, intellectually disabled man with history of the multiple endocrine neoplasia type 1 (MEN1) syndrome, a surgery in 1985 for hypercalcemia with removal of one parathyroid gland, surgery in 2007 with findings of extensively necrotic well differentiated neuroendocrine carcinoma (carcinoid tumor) of the thymus. In 2012, he presented with persistent hypercalcemia (calcium level 11.7 mg/dL [range, 8.6-10.2]), and a parathyroid hormone (PTH) level of 225 pg/mL (range, 15-65 pg/mL). He underwent a repeat neck exploration with removal of 2 small inferior and a large left superior 4.5 × 2.5 × 1.5 cm parathyroid glands, all of which showed hyperplasia on intraoperative frozen section. A small portion of the superior gland was reimplanted into the patient's forearm. Final pathology showed the presence of a focus of neuroendocrine tumor within the left superior parathyroid gland with immunostain identical to the thymic carcinoma. His postoperative PTH level was 14 pg/mL and calcium 8.5 mg/dL. A positron emission tomography-computed tomography (PET-CT) and octreotide scans revealed an extensive metastatic disease within the lung, mediastinum, and bones. RESULTS: We decided to leave a portion of the reimplanted parathyroid gland with possible metastatic thymic carcinoid in his forearm because of the presence a widespread metastatic disease and his intellectual disability that would result in noncompliance with calcium replacement in case of permanent hypocalcemia. CONCLUSION: Metastatic thymic carcinoma to the parathyroid gland has never been reported in the literature. We have described the first case and presented a challenging management dilemma.
