A rare case of hidradenitis of the scrotum: MRI findings

Clinical History

Progressive swelling and inflammation of the scrotum, penis and perineal region over the last two years, in a patient with HCV-positive chronic hepatitis and history of acute pancreatitis.

Imaging Findings

Physical examination revealed painful, massive swelling and inflammation of perineum, scrotum and penis, with thickened skin surface and presence of multiple fistulous openings draining pus. The patient was apyretic. Positive cultures from swab samples yielded Staphylococcus aureus and Corynebacterium striatum.
The patient underwent MR examination of the pelvis and perineal region to assess the extent of the suppurative process. Unenhanced images documented marked, symmetrical thickening of the skin and subcutaneous planes with abnormal signal intensity consistent with oedema and inflammation involving the medial aspect of the thighs, the perineal region, the penis and scrotum, where some small fluid areas representing pus collections were visible. Multiple enlarged lymph-nodes were seen in both inguinal regions. After intravenous gadolinium administration strong enhancement was observed in the involved skin and subcutaneous areas with small scrotal abscesses showing ring enhancement. Both testes were normal-sized and homogeneous. The adenopathies showed homogeneous enhancement with the exception of some necrotic ones on the right side.
Plain radiographs excluded the presence of air collections in the involved subcutaneous tissues.
A diagnosis of Hidradenitis suppurativa in Stage 3 according to Hurley was made and the patient underwent antibiotic therapy and surgery, consisting in incision, drainage and curettage of multiple scrotal abscesses and of a necrotic-purulent inguinal collection (corresponding to the described necrotic nodes); four setons were positioned; a diffuse serous transudation in the whole scrotum was also noticed at surgery and attributed to lymphatic stasis. After two weeks, the patient was doing well and was discharged.

Discussion

Hidradenitis suppurativa (HS) s a chronic inflammatory disease of the skin and subcutaneous tissues, occurring the axillae, perineum, and inframammary regions. It is a relatively uncommon, often debilitating disease with a chronic progressive course including remissions and exacerbations.
HS may begin in adolescence but is usually diagnosed in young adults, is more common among females and black people but its perianal localization seems to predominantly affect males. It has been suggested that poor hygiene contributes to the onset of the disease. Though its pathogenetic mechanisms are still unknown, HS is now considered a disease caused by follicular occlusion rather than an inflammatory or infectious process of the apocrine glands.

Clinically, the disease often presents with tender subcutaneous nodules that may spontaneously rupture or coalesce forming painful, deep dermal abscesses; its most advanced manifestations include fibrosis, ulceration and the formation of extensive sinus tracts. Perianal HS is associated with more debilitating outcomes, and this condition may lead to social embarrassment and to failure to seek medical treatment.
Since skin inflammation, abscesses and fistulous tract are nonspecific manifestations, the differential diagnosis for HS is wide, including dermatological and infectious diseases as well as Crohn’s disease and Fournier’s gangrene.
Hurley proposed a staging system for HS, grouping patients into three stages according to the presence and extent of cicatrisation and sinuses.
Therapies consist in long-term antibiotics, antiandrogens and surgery, with the recent introduction of anti-TNF inhibitors. However, wide surgical excision of all the affected tissue is the most effective therapy in patients with multiple interconnected sinus tracts and complex abscesses. HS has a high recurrence rate, even in surgically treated patients.

The diagnosis of HS is based on clinical evaluation. A preliminary evaluation can be performed by means of ultrasound, but this technique doesn’t allow a panoramic view of affected districts and an accurate assessment of inflammation extent. To date, only few data about MRI findings in HS are available in literature. Abscesses and inflammatory hypervascular tissues are easily identified by MRI, especially in fat-suppressed and postcontrast sequences.
As this case exemplifies, MRI is a valuable instrument for an accurate diagnosis and assessment of disease extension and severity, which allows an accurate planning of surgical approach in order to reduce the risk of incomplete excision and recurrence.

Differential Diagnosis List

Final Diagnosis

Hidradenitis of the scrotum

URL:	https://www.eurorad.org/case/8819
DOI:	10.1594/EURORAD/CASE.8819
ISSN:	1563-4086