title: Pyoderma gangrenosum preceding the onset of extranodal natural killer/T-cell lymphoma: A case report.
abstract: BACKGROUND
  Pyoderma gangrenosum (PG) is a neutrophilic dermatosis that may be associated with systemic diseases. The association of PG with lymphoid malignancies has rarely been reported. Extranodal natural killer/T-cell lymphoma (ENKTL) is a rare but aggressive entity with a poor prognosis. Here, we report the case of a patient who had idiopathic PG refractory to systemic steroids and subsequently developed ENKTL.
  
  
  METHODS
  A 70-year-old man presented with a 2-month history of intermittent fever and multifocal painful papules, plaques, and ulcerations on his extremities. The histological and culture results of the lesions were consistent with those of PG. A thorough work-up was performed and did not demonstrate any underlying systemic diseases including malignancy. The PG lesions were refractory to systemic steroid therapy. An enlarging nodule was observed over his right infraorbital area 4 months after the onset of the skin eruptions. The nodule was later biopsied and diagnosed as ENKTL by using histopathological and immunohistochemical studies. Fludeoxyglucose positron emission tomography/computed tomography revealed multiple intense fludeoxyglucose-avid masses in the bones and lungs, suggesting multiorgan metastases. The patient rejected chemotherapy and died 4 weeks after the diagnosis.
  
  
  CONCLUSIONS
  The present case indicates that in any patient with idiopathic PG refractory to conventional therapy, the presence of any underlying disease or malignancy must be thoroughly evaluated. The present case serves as a reminder that when assessing patients with PG, clinicians should increase their awareness regarding the delayed association with malignancy, even in the absence of a concomitant systemic disease at presentation. Furthermore, the prompt evaluation of any suspicious lesions in the context of PG for the possibility of a malignant nature can improve the prognosis, particularly in cases of aggressive malignancy. Understanding the cutaneous spectrum of ENKTL is crucial because of its variable clinical appearance and aggressive nature. Our case demonstrates that PG can be a presenting sign of ENKTL.
authors.affiliation: Department of Dermatology, Taipei Medical University Hospital, Taipei, Taiwan Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ting-Hua
authors.initials: TH
authors.lastname: Yang
authors.forename: Chung-Hong
authors.initials: CH
authors.lastname: Hu
authors.forename: Hsiou-Hsin
authors.initials: HH
authors.lastname: Tsai
mesh_terms: D000368:Aged; D006801:Humans; D054391:Lymphoma, Extranodal NK-T-Cell / Q000145:classification* / Q000175:diagnosis*; D008297:Male; D017511:Pyoderma Gangrenosum / Q000150:complications*