Herpes Simplex Mastitis in an Adolescent Woman: Clinical and Ultrasound Features.

Herpetic mastitis is extremely rare, and its imaging findings remain unclear. We report a case of herpes simplex mastitis in an adolescent woman and describe the clinical and ultrasound features. The patient showed unilateral nipple and areolar skin thickening and axillary lymphadenopathy on B-mode ultrasonography. Doppler ultrasonography revealed multiple linear and branching blood flows in the areolar area. The lesion was verified as herpes simplex mastitis via a skin biopsy. This report shows that the radiologic features of herpes simplex mastitis may be similar to those of Paget's disease because of localized nipple and areolar skin thickening and increased vascularity. Copyrights

INTRODUCTION

Herpes simplex virus (HSV) causes various diseases ranging from mild uncomplicated mucocutaneous infection to life-threatening conditions. The most common site of HSV infection is the skin and mucosal membrane, especially in the oral and genital areas (1). The breast is a rare location for HSV infection, and only one previous case report has described the imaging findings of HSV mastitis (2). Herein, we report a case of HSV mastitis in an adolescent woman and describe its clinical and ultrasound (US) features. We evaluated the breast lesion by using B-mode and Doppler ultrasonography. To our knowledge, the vascular US features of HSV mastitis have not been previously reported.

CASE REPORT

A 17-year-old nulligravida adolescent woman presented to a breast surgeon with a 1-year history of clear nipple discharge and itching on the right nipple and areola. She received topical steroid treatment at a local clinic, but her symptoms did not improve. She had no other history of breast disease or a family history of breast cancer. She was otherwise healthy and did not take any medication. A physical examination of the right breast revealed an eczematous oozing patch and tiny vesicles on the right nipple and areolar area (Fig. 1A, B). Several ipsilateral axillary lymph nodes were palpable. The patient did not present any similar symptoms in her left breast. Considering her young age, initial imaging was performed using ultrasonography rather than mammography.

Fig. 1

Herpes simplex mastitis in a 17-year-old adolescent, presenting with a 1-year history of clear nipple discharge and itching on the right nipple and areola.

A, B. Photograph of the right nipple (A) and dermoscopic image of the right periareolar area (B) reveal an eczematous oozing patch and tiny vesicles.

C. Ultrasonography shows localized hypoechoic skin thickening in the right periareolar area. The lesion extent is 25.0 mm, and the skin thickness is 3.5 mm.

D. Color Doppler ultrasonography shows multiple linear and branching blood flows in the right periareolar skin.

E. Ultrasonography of the right axilla reveals multiple enlarged lymph nodes with cortical thickening.

F. Hematoxylin and eosin staining (× 40) performed during a pathologic examination shows a dense neutrophilic exudate with overlying sloughed epithelial cells containing viral inclusions.

On US examination, the right periareolar skin was thickened and hypoechoic (Fig. 1C). The lesion extent was 25.0 mm, and the skin thickness was 3.5 mm. Increased vascularity was detected on color Doppler ultrasonography (Fig. 1D). Multiple branching blood flows were also noted in the areolar area. Multiple enlarged lymph nodes less than 20 mm in size were present in the right axilla. These lymph nodes showed cortical thickening (Fig. 1E). On the basis of the US findings, we considered the patient had an uncommon breast infection or Paget's disease. We excluded allergic contact dermatitis because topical steroid application did not improve her clinical symptoms.

A skin punch biopsy of the areolar area revealed a dense neutrophilic exudate with overlying sloughed epithelial cells containing viral inclusions, suggesting herpetic infection (Fig. 1F). The patient was treated with oral famciclovir for 18 days. After treatment, the symptoms completely resolved. A posttreatment skin punch biopsy revealed that the infection had completely resolved. The patient also had a painful erythematous oozing patch in the oral cavity and the left third finger. Considering this fact, the nipple and areolar lesions may have been caused by HSV autoinoculation.

DISCUSSION

HSV infection of the breast is very rare. The majority of herpetic breast infections are related to HSV-1 infection, and HSV-2 infection is exceptional (2345678). The common clinical features of a herpetic breast infection are pruritus and painful swelling with dermatologic manifestations, including swelling, erythema, small vesicles, and excoriation. Moreover, unilateral breast infections are more common. The lesion is usually confined to the nipple-areolar complex and periareolar area (6). Nevertheless, a few cases of cutaneous dissemination to the whole breast have been reported (23).

Prior reports revealed three sources of HSV transmission to the breast. The most frequent etiology of HSV mastitis is an infant-maternal transmission during breastfeeding (35). In nonlactating women, HSV mastitis can occur via autoinoculation or oral sexual contact (478). Autoinoculation may occur from recurrent orolabial herpetic infections in the patients themselves. Considering these transmission modes, the nipple-areolar complex and periareolar area can be vulnerable to HSV mastitis.

Few reports have documented the imaging findings of HSV mastitis. In a case report, Soo and Ghate (2) reported that HSV mastitis showed diffuse asymmetry and skin thickening on mammography and skin thickening and axillary lymphadenopathy on ultrasonography. A physical examination revealed excoriation at the nipple tip and diffuse peau d'orange breast skin edema, mimicking inflammatory breast cancer or another mastitis etiology. Unlike the patient in the prior report, our patient showed a more localized infection, confined to the nipple and areola, which is a more frequent form of herpetic breast infection than is the disseminated form. In our patient, ultrasonography revealed localized hypoechoic skin thickening at the nipple and areola. We also performed color Doppler ultrasonography, which revealed multiple linear and branching blood flows in the localized skin thickening at the nipple and areola. To our knowledge, these Doppler US findings have not been previously reported.

The differential diagnosis of localized hypoechoic skin thickening in the nipple-areolar complex is Paget's disease as well as various benign processes, such as breast eczema, allergic contact dermatitis, or irritant dermatitis (9). Breast eczema typically occurs bilaterally. Paget's disease of the nipple-areolar complex is characterized by the presence of neoplastic cells in the epidermis. It shows unilateral skin changes and is associated with a breast mass or calcifications (10). Distinguishing HSV mastitis clinically and radiologically from Paget's disease is difficult. However, skin thickening is a major radiological finding in HSV mastitis, and a mass, calcification, or ductal dilatation is rare. Although a pathologic examination is necessary to exclude a malignant lesion such as Paget's disease, HSV mastitis should be included in the differential diagnosis of unilateral nipple and areolar skin thickening with increased vascularity, especially when the patient has other skin lesions suggestive of herpetic infection.

In conclusion, HSV infection of the nipple and areolar area is an uncommon entity that may easily be misdiagnosed. The radiological findings of HSV mastitis are similar to those of Paget's disease because of localized skin thickening and hypervascularity. Although tissue biopsy is essential to rule out malignant processes and to confirm the diagnosis, HSV mastitis should be included in the differential diagnosis of unilateral skin thickening in the nipple-areolar complex in women, especially when symptoms do not improve after topical steroid application.