the major sites of breast cancer metastasis in decreasing prevalence are the lungs , bone , liver , adrenal , and brain . cutaneous metastasis from internal malignancies is rare with a reported incidence between 0.7% and 9% and it may be a sign of cancer recurrence . skin metastases from breast cancer have many forms : telangiectatic carcinomas , erysipeloid carcinomas ,  en cuirasse carcinoma en cuirasse is very rare and occurs in only 3% of cutaneous metastasis cases . carcinoma en cuirasse is described as small , multiple erythematous nodules which can enlarge and coalesce to form plaques.18f - fluorodeoxyglucose - positron emission tomography / computed tomography ( fdg - pet / ct ) can scan the whole body for metastases in one exam , whereas serial cts are required to accomplish the same task . the patient was a 36-year - old female who presented with pain under the left arm . the ultrasound revealed a 2.5 cm irregular mass in the upper outer quadrant of the left breast and a subsequent mammogram showed an asymmetric density in the same region . left lumpectomy removed a 4.9 cm mass and pathology confirmed it as er+/pr/her-2 intermediate - grade ductal carcinoma in situ ( dcis ) with positive margins . left breast re - excision was done and there was no evidence of residual disease . sentinel lymph node biopsy was negative and fdg - pet / ct showed only postsurgical changes [ figure 1 ] . about 3 years later , the patient presented with multiple skin nodules on the chest and upper left arm . fdg - pet / ct revealed extensive metastatic disease involving left axillary lymph nodes , left suprascapular muscle , chest , and left upper arm [ figure 2a  c ] . biopsies were done on the chest , left suprascapular muscle , and left axillary lymph nodes and they showed poorly differentiated er+/pr/her-2 adenocarcinoma . 36-year - old female presented with pain under the left arm and was diagnosed with intermediate - grade dcis . fdg - pet / ct maximum intensity projection ( mip ) image shows only postsurgical changes with no evidence of residual or metastatic disease . 36-year - old female presented with pain under the left arm and multiple skin lesions 3 years after surgery for dcis . ( a ) fdg - pet / ct maximum intensity projection ( mip ) image shows cutaneous metastases ( arrows ) on the chest and left upper extremity . ( b ) pet and ( c ) hybrid pet / ct images , axial view show breast cancer infiltration in the left suprascapular muscle and left axillary lymph nodes ( arrows ) ( suv 7.09 ) . this is the first case to show fdg - pet / ct images of suprascapular muscle metastasis from breast cancer . skeletal muscle is an unusual site for breast cancer metastasis and it occurs by the hematogenous route . abdomen , back , and upper extremities are less common sites of skin metastasis . in our patient , cutaneous metastasis occurred in the chest and left upper extremity . our patient was first diagnosed with breast cancer at the age of 36 and breast cancer in this age group is very rare . young age ( less than 40 years ) is an independent predictor of tumor recurrence following breast - conserving surgery . our patient had lumpectomy in the left breast and the cancer recurred 3 years after the surgery . according to the biopsy report , she had er+/pr/her-2 ductal carcinoma . interestingly , younger patients with er + ve tumors have a poorer disease - free survival than those with er ve tumors . ultrasound ( us ) and ct mostly focus on the size of the lymph nodes , while fdg - pet / ct looks at the biological activity of tumors . intramuscular hot spots on pet / ct scans should be considered as a sign of metastasis , even in the absence of abnormalities on ct scans . it is difficult to detect skeletal muscle metastasis with 
 the generally used ct scans . in the present case , the extent of breast cancer recurrence was clearly demonstrated by the pet / ct exam . fdg - pet / ct has 93% sensitivity and 100% specificity in detecting breast cancer recurrence . aukema et al . , even suggested that pet / ct can replace conventional imaging in patients with breast cancer recurrence . pet scanning can reveal unexpected sites of metastasis . this case has demonstrated that fdg - pet / ct is useful in demonstrating the extent of breast cancer recurrence . skin lesions in a patient with history of breast cancer should raise the suspicion of cancer recurrence .
our patient was a 36-year - old female diagnosed with grade ii er+/pr/her-2  ductal carcinoma in situ ( dcis ) in the left breast . 
 she underwent left lumpectomy and received treatment with tamoxifen and radiotherapy . 
 three years later , she presented with multiple diffused skin nodules on the chest and upper left arm . 18f - fluorodeoxyglucose - positron emission tomography / computed tomography ( fdg - pet / ct ) exam showed widespread metastasis in the chest , upper left arm , left axillary lymph nodes , and left suprascapular muscle . 
 fdg - pet / ct imaging of breast carcinoma en cuirasse is very rare . 
 fdg - pet / ct is useful in detecting recurrent breast cancer .