Metastatic melanoma presenting as a breast mass - role of radiologist as a clinician

Abstract

Breast tissue can be the host of not only many benign and malignant tumors but can also be a metastatic site for various tumors such as leukemia, lung cancer, and melanoma. This report describes an unusual case of a 43-year-old female who presented with a new palpable breast lump and several similar extramammary lumps on her skin. A melanoma panel, consisting of S100, HMB45, and Melan-A stains, was included in the pathology evaluation due to diagnostic suspicion of the radiologist and revealed metastatic melanoma. This case highlights the importance of detailed history and relevant physical exam as well as clinical and imaging correlation. It serves as a reminder to radiologists to include metastatic melanoma in the differential of suspicious subcutaneous breast masses, especially in patients with multiple subcutaneous lumps in the body or abnormal skin findings.

Fig 1

(a, b) Initial diagnostic mammogram of left breast at symptom onset (a) (craniocaudal) CC tomosynthesis slice, (b) (mediolateral oblique) MLO tomosynthesis slice – demonstrated a mass at 10-o’ clock ( pink arrow), corresponding to the area of the palpable abnormality ( skin marker).

Fig 2

Transverse ultrasound image of the left breast mass at 2-o’ clock showed stable findings of an oval circumscribed hypoechoic mass with echogenic biopsy clip ( red arrow) consistent with biopsy proven fibroadenoma. (Color version of figure is available online.)

Fig 3

(a, b) Ultrasound images (a transverse image and b longitudinal image) of the palpable abnormality in the left breast showed a slightly irregular hypoechoic subcutaneous mass with indistinct and microlobulated margins at 10-o’ clock, 6 cm from the nipple.

Fig 4

S100 stain with ×20 magnification showed strongly positive nuclear and cytoplasmic staining.

Fig 5

Mel A stain with ×10 magnification demonstrated positive cytoplasmic staining supporting a melanocytic origin of the tumor cells.

Fig 6

Maximum intensity projection coronal image from PET-CT of the whole body revealed over 200 FDG-avid (Fluorine 18 fluorodeoxyglucose) metastatic lesions.

Fig 7

PET-CT axial image through mid-chest demonstrated that besides the BIRADS 4 mass located at 10 o’ clock, the two left breast masses ( yellow arrows), previously identified on ultrasound at 10-o'clock were also FDG avid. (Color version of figure is available online.)

Fig 8

PET-CT sagittal image showed an extradural spinal lesion at the level of T6 vertebra ( black arrow).

Fig 9

MRI spine sagittal image showed an extradural spinal lesion at the level of T6 vertebra ( blue arrow). (Color version of figure is available online.)