Myeloid Sarcoma with a PICALM–MLLT10 Fusion Presenting as an Isolated Mediastinal Mass in a Middle-Aged Asian Male: A Case Report

Jorge López Villegas^1, , Leonardo Granados Altamirano¹, José Rojas Rodríguez¹ and Betzabé Rojas Mena²

¹Hematology Department, Dr. Rafael Ángel Calderón Guardia Hospital, Caja Costarricense de Seguro Social, San José, Costa Rica

²1Hematology Department, Dr. Rafael Ángel Calderón Guardia Hospital, Caja Costarricense de Seguro Social, San José, Costa Rica

Cite this paper:
Jorge López Villegas, Leonardo Granados Altamirano, José Rojas Rodríguez and Betzabé Rojas Mena. Myeloid Sarcoma with a PICALM–MLLT10 Fusion Presenting as an Isolated Mediastinal Mass in a Middle-Aged Asian Male: A Case Report. American Journal of Medical Case Reports. 2025; 13(7):37-40. doi: 10.12691/ajmcr-13-7-1

Abstract

Myeloid sarcoma (MS), also known as granulocytic sarcoma or chloroma, is a rare extramedullary manifestation of acute myeloid leukemia (AML). Mediastinal presentation is exceedingly uncommon and may lead to misdiagnosis, particularly when hematologic parameters are preserved. We report the case of a 44-year-old male who presented with constitutional symptoms and an isolated anterior mediastinal mass without peripheral blood abnormalities. Diagnosis was established through flow cytometry, histopathology, and immunohistochemistry. Molecular profiling revealed a complex mutational landscape including PHF6, TP53, WT1 mutations, and a PICALM–MLLT10 fusion. The patient was treated with AML-directed chemotherapy and remains under close surveillance. This case highlights the diagnostic challenges and prognostic implications of extramedullary AML with rare genetic alterations.

Keywords:
Myeloid sarcoma acute myeloid leukemia mediastinal mass extramedullary leukemia

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

References:

[1]	Avni B, Koren-Michowitz M. Myeloid Sarcoma: Current Approach and Therapeutic Options. Ther Adv Hematol. 2011 Oct; 2(5): 309–16.
[2]	Shallis RM, Gale RP, Lazarus HM, Roberts KB, Xu ML, Seropian SE, et al. Myeloid sarcoma, chloroma, or extramedullary acute myeloid leukemia tumor: A tale of misnomers, controversy and the unresolved. Blood Reviews. 2021 May 1; 47: 100773.
[3]	Liang J, Yang L, Yang B, Tian Y, Ren J, Yang L. Clinical characteristics, treatment options, and prognosis of myeloid sarcoma: analysis using the SEER database. Hematology. 2023 Dec 31; 28(1): 2247898.
[4]	Aguilar J, Padmanabhan D, Dyson G, Balasubramanian SK. Meta-Analysis of Clinicopathological and Biological Characteristics of Myeloid Sarcoma. Blood. 2023 Nov 2;142: 3811.
[5]	Mori T, Nagata Y, Makishima H, Sanada M, Shiozawa Y, Kon A, et al. Somatic PHF6 mutations in 1760 cases with various myeloid neoplasms. Leukemia. 2016 Nov; 30(11): 2270–3.
[6]	Daver NG, Iqbal S, Renard C, Chan RJ, Hasegawa K, Hu H, et al. Treatment outcomes for newly diagnosed, treatment-naïve TP53-mutated acute myeloid leukemia: a systematic review and meta-analysis. J Hematol Oncol. 2023 Mar 6; 16(1): 19.
[7]	Niktoreh N, Weber L, Walter C, Karimifard M, Hoffmeister LM, Breiter H, et al. Understanding WT1 Alterations and Expression Profiles in Hematological Malignancies. Cancers. 2023 Jul 4; 15(13): 3491.
[8]	Wang J nuo, Ye B, Cheng F, Yang L, Hu Y, Zheng G, et al. PICALM-MLLT10 fusion gene in hematological neoplasms: clinical features, current practices, and prognoses. Hematology. 2024 Dec 31; 29(1): 2423324.
[9]	Jian X, Cha J, Lin Z, Xie S, Huang Y, Lin Y, Zhao H, Xu B, Luo Y. Real-world experience with venetoclax-based therapy for patients with myeloid sarcoma. Discover Oncology. 2024 Jun 5; 15(1): 210.
[10]	Shatilova A, Girshova L, Zaytsev D, Budaeva I, Mirolyubova Y, Ryzhkova D, Grozov R, Bogdanov K, Nikulina T, Motorin D, Zammoeva D. The myeloid sarcoma treated by Venetoclax with hypomethylating agent followed by stem cell transplantation: rare case report. BMC women's health. 2021 May 1; 21(1): 184.