|LETTER TO THE EDITOR
|Year : 2017 | Volume
| Issue : 3 | Page : 253-254
Type 2 lepra reaction presenting as fever of unknown origin identified on 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography
Piyush Chandra1, Satish Nath1, Srinivas Chakravarthy2, Jemima Kingsley3
1 Department of Nuclear Medicine, MIOT International, Chennai, Tamil Nadu, India
2 Department of Pathology, MIOT International, Chennai, Tamil Nadu, India
3 Department of Microbiology, MIOT International, Chennai, Tamil Nadu, India
|Date of Web Publication||13-Jun-2017|
Department of Nuclear Medicine, MIOT International, 4/112, Mount Poonamalle Road, Manapakkam, Chennai - 600 089, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Chandra P, Nath S, Chakravarthy S, Kingsley J. Type 2 lepra reaction presenting as fever of unknown origin identified on 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography. Indian J Nucl Med 2017;32:253-4
|How to cite this URL:|
Chandra P, Nath S, Chakravarthy S, Kingsley J. Type 2 lepra reaction presenting as fever of unknown origin identified on 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography. Indian J Nucl Med [serial online] 2017 [cited 2021 May 13];32:253-4. Available from: https://www.ijnm.in/text.asp?2017/32/3/253/207894
A 25-year-old male, with no prior history of any illness, presented with high-grade fever for 2 weeks and tender lymphadenopathy in the bilateral axilla/groin with 1-day history of erythematous lesions in dorsal aspect of both forearms. Routine laboratory investigations for fever were negative, and positron emission tomography/computed tomography (PET/CT) was done for localization of infection. Maximum intensity projection images ([Figure 1]a,[Figure 1]b,[Figure 1]c,[Figure 1]d) showed increased focal 18 F-fluoro-2-deoxyglucose (FDG) uptake in enlarged lymph nodes in the bilateral inguinal region and axilla ([Figure 1]a) with diffuse FDG uptake in skin of bilateral pinna (short blue arrow, ([Figure 1]b), skin of scrotum (long blue arrow, ([Figure 1]c), skin lesions in bilateral forearm (black arrowhead, ([Figure 1]d), and marrow of axial skeleton. Slit skin smear (SSS) from the skin of pinna using modified Ziehl–Neelsen stain was positive for Mycobacterium leprae bacilli with bacillary index (BI) score 4+ (pink stain, bold black arrow, ([Figure 1]e). Biopsy from forearm lesions showed periadnexal and perivascular inflammation with predominantly neutrophils with a few foamy histiocytes (black arrow, ([Figure 1]f) – suggestive of erythema nodusum leprosum (ENL).
|Figure 1: PET MIP images (a-d) increased FDG uptake in enlarged lymph nodes in the bilateral inguinal region and axilla (a) with diffuse FDG uptake in skin of bilateral pinna (b), skin of scrotum (c), skin lesions in bilateral forearm (d). Slit skin smear from pinna using modified ZN stain was positive for Mycobacterium leprae with bacillary index (BI) score 4+ (e). Biopsy from forearm lesions showed periadnexal and perivascular inflammation (f) . suggestive of erythema nodusum leprosum (ENL)|
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Contrary to the popular belief, leprosy is still highly prevalent in the developing countries. Type 2 lepra reaction/ENL is an immunological reaction that occurs in borderline/lepromatous spectrum. Arthus-like reaction with multiorgan immune complex deposition has been postulated as the most likely mechanism. Rarely, ENL may be the initial presenting symptoms with high-grade fever, arthritis, lymphadenopathy, and nephropathy, causing delay in clinical diagnosis. SSS is usually taken from cooler areas of the body such as ear lobules which yields higher BI as compared to other sites. Biopsy of skin lesions showing neutrophilic infiltration of vessel wall (vasculitis) differentiate type 1 from type 2 lepra reaction, in which lymphocytic infiltration is more common. PET/CT is a highly sensitive investigation in identifying site of infection/inflammation in patients with fever of unknown origin (FUO). In highly endemic region, evidence of systemic inflammation and typical skin lesions on PET/CT, such as that described above, leprosy reactions should be included in one of the differential diagnoses of FUO.
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