title: Papulonecrotic tuberculid-clinicopathologic and molecular features of 12 Indian patients.
abstract: BACKGROUND
  Papulonecrotic tuberculid (PNT) is said to be a hypersensitivity reaction to M. tuberculosis. Some reports indicate that organisms are demonstrable by polymerase chain reaction (PCR).
  
  
  METHODS
  We describe 12 patients with PNT over 6 years. We reviewed the histopathologic features, clinical data and follow-up. PCR for M. tuberculosis DNA was done in all cases.
  
  
  RESULTS
  There were 7 men and 5 women. The ages ranged from 3-58 years. Upper limbs were commonly involved (8 cases). All patients had multiple papulonodular lesions, 5 showed ulceration and scarring. Mantoux test was strongly positive in all. Seven patients had systemic tuberculosis. On microscopy, necrosis was seen in 11 cases, varying from minimal to extensive. Epithelioid granulomas were common, except for 1 case with palisading and interstitial patterns. The infiltrate showed mostly lymphocytes, while 3 cases showed eosinophils. Vasculitis was seen in 8 cases. Two cases had dermal mucin, one also with interface dermatitis. This patient had concurrent LE. Mycobacterial DNA was detectable by PCR in 3 cases. Seven patients showed improvement/resolution of lesions on treatment.
  
  
  CONCLUSIONS
  PNT is a rare disease. A positive PCR reiterates the question whether these are "tuberculids". PNT may be better classified as true cutaneous tuberculosis and patients screened for systemic disease.
authors.affiliation: Departments of Pathology & Dermatology, St. John's Medical College & Hospital, Bangalore, India.
authors.forename: Rajalakshmi
authors.initials: R
authors.lastname: Tirumalae
authors.affiliation: Departments of Pathology & Dermatology, St. John's Medical College & Hospital, Bangalore, India.
authors.forename: Inchara K
authors.initials: IK
authors.lastname: Yeliur
authors.affiliation: Departments of Pathology & Dermatology, St. John's Medical College & Hospital, Bangalore, India.
authors.forename: Meryl
authors.initials: M
authors.lastname: Antony
authors.affiliation: Division of Infectious Diseases, St. John's Research Institute; John Nagar, Bangalore, India.
authors.forename: Geojith
authors.initials: G
authors.lastname: George
authors.affiliation: Division of Infectious Diseases, St. John's Research Institute; John Nagar, Bangalore, India.
authors.forename: John
authors.initials: J
authors.lastname: Kenneth
keywords: cutaneous tuberculosis; papulonecrotic tuberculid