Squamous‐Cell Carcinoma Arising in a Pilonidal Sinus: A Case Report and Review of the Literature

A curative cryosurgical technique for advanced cancer of sacrococcygeal pilonidal sinuses

“…Malignant transformation of SPD can occur after decades of neglect or of persistently recurring lesions after successive surgical procedures, often with histories of 10–35 years' duration 1–10, 12–23. In the consulted literature, there is a total of 52 patients (44 males and only 8 females) with a mean age of 53 years 1–10, 13–24. Nine cases had 40–62 years' duration 1, 4, 14, 17.…”

“…Sacrococcygeal pilonidal disease (SPD) is a common and well‐recognized entity that occurs most frequently in men 1–10. Its most common complications are: recurrent sinuses, abscess formation, and local cellulitis.…”

“…Other, less frequent, are osteomyelitis of the sacrum or coccyx and malignant degeneration of the cyst wall or sinus tract 1–10. Notwithstanding the high incidence of pilonidal sinus, its malignant transformation is rare, around 0.1%, and occurs mostly in chronic, recurrent, and neglected primary lesions, with eventual poor prognosis 1–10. During World War II, 86,333 American soldiers were treated for pilonidal sinuses and no one had neoplastic degeneration 1, 10.…”

Fine-needle aspiration cytology of metastatic squamous-cell carcinoma arising in a pilonidal sinus, with literature review

“…2 Presentation with inguinal lymph node metastasis has been reported to occur in 14% of patients. 1,2 Patients who present with inguinal adenopathy have a very poor prognosis, with no recorded cases surviving beyond 2 yr. 1,2,12,13 Including the present case, 44 of 49 total cases (90%) with malignant degeneration were squamous-cell carcinomas. In the 44 patients with squamous-cell carcinoma, only 9 (20%) had inguinal adenopathy (Tables I and II).…”

“…2 Pilonidal carcinoma has a rather distinctive appearance, with the diagnosis frequently suspected by inspection, based on the presence of a long-standing and persistent pilonidal sinus with drainage, sudden rapid growth, overgrowth above the skin level, friability, ulceration, hemorrhage in the tissues, external bleeding, and most commonly, bleeding in a sinus that has been present for many years. [12][13][14] The tumor tends to be slow-growing, but with a tendency toward aggressive local invasion. 1 Local recurrence is common, with rates of 34-42% reported, 1,2 and tends to occur early (16 mo) following diagnosis.…”