Role of 18 F-FDG-PET/CT in an AML-M5a Subtype Patient with Rare Constellation of Hemophagocytic Lymphohistiocytosis & Bilateral Multiple Breast Chloromas

TL;DR

This case study shows how PET/CT imaging helped diagnose and monitor a rare combination of AML-M5a, HLH, and breast chloromas in a single patient.

Contribution

Highlights the role of 18F-FDG-PET/CT in diagnosing and monitoring a rare coexistence of AML-M5a, HLH, and chloromas.

Findings

18F-FDG-PET/CT identified multiple lymph nodal and marrow lesions and later detected bilateral breast chloromas.

PET/CT guided biopsy sites and monitored treatment response for both HLH and AML.

The case emphasizes the importance of nuclear medicine physicians recognizing complications in AML with poor prognostic factors.

Abstract

We report a treated case of acute myeloid leukemia (AML-M5a subtype) with monocytic differentiation (AMoL) presenting with fever and body pains. Initial
18
F-FDG-PET/CT (
18
F-flurodeoxyglucose positron emission tomography/computed tomography) identified multiple lymph nodal, and marrow lesions. Biopsy confirmed hemophagocytic lymphohistiocytosis (HLH). Post HLH treatment, follow-up PET/CT demonstrated unsuspected FDG avid bilateral breast lesions (
n
 = 5), which proved to be chloromas, that is, extranodal manifestation of AML.
18
F-FDG-PET/CT has helped not only in identifying the various sites of disease involvement but also in guiding the sites for biopsy. Finally,
18
F-FDG-PET/CT was useful in monitoring therapy response for both these coexisting pathologies, which are said to be resistant to treatment based on FLT3-ITD tyrosine kinase-3 internal tandem duplication mutation positivity and high-grade AML status. This case represents a rare constellation of different etiologies that needed to be differentiated. It also emphasizes the challenges in interpreting PET/CT findings, especially in difficult clinical scenarios. Disease distribution in HLH/presence of chloromas, etc., can mimic stage IV lymphoma in a known case of AML. So the nuclear medicine physician should be aware of the different complications in the background of AML, especially in patients with poor prognostic factors.

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