CASE 17106 Published on 07.01.2021

Myeloid sarcoma of the breast: a rare case

Section

Breast imaging

Case Type

Clinical Cases

Authors

Dr Sonali Sharma (MD), Dr. Jeevanjot Matharoo (MD), Dr Kanika Kaushal (MD), Dr Vidhi Bakshi (MD), Dr Jyoti Arora (CCST MD  DMRE MBBS), Dr. Nupur Akash Patel( DMRD), Dr Ruchika Goel (MD)

Medanta The Medicity Hospital Gurugram, India

Patient

27 years, female

Categories
Area of Interest Breast, Pelvis ; Imaging Technique MR
Clinical History

A 27-year-old lactating female on treatment for Acute Myeloid Leukemia (FLT-3 mutation-positive) presented with complaints of a firm, immobile lump in the outer half of the right breast and a fixed lump in the right axillary region.

Imaging Findings

We could not acquire a mammogram because of the very poor ambulatory status of our patient.

Breast ultrasound showed a well-circumscribed large mass with heterogeneous low echogenicity and internal vascularity. Few other similar lesions were noted in the upper outer quadrant of the right breast. Enlarged discrete and conglomerated right axillary nodes with loss of fatty hila were seen.

On Contrast-Enhanced Magnetic Resonance Imaging (CEMRI) the right breast was enlarged, engorged, and had skin thickening. There were multiple well-circumscribed and irregular intensely enhancing lesions of variable sizes in the outer half of the right breast revealing restricted diffusion, low Apparent Diffusion Coefficient Values(ADC), and Type 3 curves. Multiple rounded, discrete, and conglomerate nodes were seen in the right axilla. Prominent right internal mammary nodes were also seen.

Histopathological and Immunohistochemical evaluation revealed features favouring the diagnosis of Myeloid Sarcoma of the breast with positivity for CD33, CD117, MPO (myeloperoxidase), negativity for CKCK (creatine kinase), GATA3, ER (estrogen receptor), CD68, and focal patchy positivity for CD 34.

Discussion

Myeloid sarcoma (MS) is an extramedullary tumour which was first described in literature by Burns in 1811. King in 1853 was the first to call it chloroma (due to its green colour attributed to the enzyme myeloperoxidase (MPO). Dock in 1893 established its association with leukaemia.[1] Myeloid sarcoma is also known as granulocytic sarcoma, monocytic sarcoma, extramedullary myeloid cell tumour, myeloblastoma, and chloroma [2].

Myeloid sarcoma can occur in subcutaneous tissue, orbit, lymph nodes, small intestine, pelvic organs, and the brain [3,4], testis or the breast [5,6]. In 2–14% of acute myeloid leukaemia (AML) patients, myeloid sarcoma can be found, though it is most commonly seen associated with chronic myeloid leukaemia or myelodysplastic syndromes [6,7,8]. Breast involvement without a leukemic or myeloproliferative disorder is extremely rare [9,10,11]. However rarely myeloid sarcoma can present with isolated extramedullary mass without any previous or coexisting leukaemia [12,13]. The isolated cases may subsequently develop AML [12].

Overall, MS has been classified into four types: (i) primary MS, (ii) MS as an extramedullary manifestation of AML, (iii) MS as isolated recurrence of AML and

(iv) MS with coexisting bone marrow relapse of AML.[14]

Histopathological examination with immunohistochemical testing [15] remains the gold standard of diagnosis, with MPO stain often strongly positive in myeloid sarcoma [16]

Clinically, non-specific symptoms are seen in MS which include mostly painless or painful breast lumps involving one or both breasts [17]. Breast skin involvement and axillary lymph node enlargement may or may not be seen. Sonological findings of MS are variable. While some researchers like Thachil et al. have reported homogenous areas of low attenuation, with well-or-ill-defined margins [18] others like Guermazi et al. [19] have reported that breast masses in myeloid sarcoma were irregularly shaped, heterogeneous, hypoechoic masses with visible posterior acoustic shadows. Some researchers have documented cases with hamartoma like appearance as well.[20]

In our case, the mass lesions were visualized as hypoechoic lesions with circumscribed margins creating an overlap with the imaging features of the benign masses like fibroadenomas, benign phyllodes and granulomatous mastitis.[20].

On CEMRI nonspecific findings such as variably enhancing masses and non-mass enhancements have been reported.[21]

Histopathology along with immunohistochemistry for CD68/KP1, MPO, CD99, CD68, CD117, CD33, CD13, CD30, CD56, lysozyme is the markers for tumours myeloid differentiation.[22]. Our patient was positive for CD33, CD117, very strongly positive for MPO and showed patchy positivity for CD34 (12)

Treatment regime includes AML type chemotherapy regime with suggested radiotherapy in cases with massive tumours with spinal cord compression.MS has the same prognosis as underlying leukaemia. [23]

Differential Diagnosis List
Myeloid sarcoma of the breast
Fibroadenoma
Hamartoma
Granulomatous mastitis
Phyllodes tumour
Haematoma
Final Diagnosis
Myeloid sarcoma of the breast
Case information
URL: https://www.eurorad.org/case/17106
ISSN: 1563-4086
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