Radiology of malignant degeneration of pilonidal sinus: Report of a case and review of the literature

Abstract

Pilonidal sinus disease is a frequent and recurrent pathology in young adults, with a male predominance, while malignant transformation of the pilonidal sinus is a rare complication, it occurs in 0.1% of patients, with a poor prognosis. Early surgical removal of the primary lesion remains the best treatment. We report a case of malignant transformation of pilonidal disease into squamous cell carcinoma.

Keywords: Malignant transformation; Pilonidal sinus; Squamous cell carcinoma.

Fig. 1

Axial and coronal sections of a pelvic MRI (A, B) show intergluteal mass with irregular and budding contours, intensely and heterogeneously enhanced after contrast, extending towards the sacrum without rectal extension (arrow). Axial section of a pelvic MRI (A, C) showing left inguinal adenopathy, heterogeneously enhanced after contrast, delineating central necrotic areas (Asterix).

Fig. 2

Axial section of MRI pelvic (D, E) showing diffusion hypersignal of the intergluteal mass and inguinal adenopathies (arrow), diffusion restriction suggests the tumoral nature of the mass.

Fig. 3

Axial section of a pelvic CT scan (F, G, H) showing the same findings as MRI: the presence of inguinal adenopathies associated with left subcutaneous nodules, enhanced after contrast (arrow head). Axial section of a thoracic CT scan (I, J): absence of mediastinal adenopathy or pulmonary metastasis.

Fig. 4

Axial section of an enhanced CT (I, J, K) showing the appearance of voluminous tissue mass lysing the left iliac bone and invading the iliac vascular pedicle (arrow), with an increase in size of the subcutaneous nodule (arrowhead).

Fig. 5

Axial section of an enhanced CT (L, M) showing the appearance of necrotic mediastinal lymphadenopathy (arrowhead) and an excavated pulmonary nodule (arrow).