Massive Squamous Cell Carcinoma Arising From Hidradenitis Suppurativa With Marked Hypercalcemia and Neutrophilia

A 36-year-old woman with a 19-year history of Hidradenitis suppurativa (HS), a chronic skin disease, developed a large tumor in her buttock, which was diagnosed as stage 4 squamous cell carcinoma (SCC) arising from HS. The patient had severe anemia, hypercalcemia, and neutrophilia. The tumor cells were mostly positive for granulocyte colony-stimulating factor (G-CSF) and parathyroid hormone-related peptide (PTHrP), proteins that were also found in high levels in the patient's serum. The patient's condition rapidly deteriorated, developing sepsis, acute renal failure, and lung metastasis, and she died on the 47th day of hospitalization. The study highlights the risk of SCC development from HS, which occurs in 4.6% of HS lesions, with a mean time from HS onset to SCC development of 25.5 years and a mortality rate of 58.7%. The study also emphasizes the role of G-CSF and PTHrP in the progression of the disease.