Case 24
HISTORY:
The patient is a 27 year old male who presented with history of
fever and enlarged neck nodes for the last 2 weeks. On examination there
were matted lymph nodes in the left upper deep cervical region.
FNA of the lymph nodes was performed and the cytological preparations were stained with
MGG. The two images 1 & 2 presented here were photographed with a 100x oil
immersion objective. Then, the images were digitized from color prints of
the photomicrographs using an Intel PC camera
Send your answers to:
Debdatta Basu, MD at
ddbasu@satyam.net.in
Associate Professor of Pathology, JIPMER, Pondicherry, India
RESULTS:
The correct answer is "negative images of tubercle bacilli".
The diagnosis
of tuberculous lymphadenitis - AFB positive was offered. The FNA smears of
the lymph node showed degenerating and viable lymphocytes and neutrophils in
a necrotic background. No granuloma reaction was evident. Closer examination
of the background revealed many negatively stained rod-shaped structures
(negative images of tuberculous bacilli) as observed in Figures 1 & 2.
Subsequent staining of the smear with ZN stains revealed numerous acid-fast
bacilli (see Figure 3 below). The patient was HIV positive, this fact was known
later.
Total responses received = 8
Negative images / atypical mycobacteriosis = 2
Histoplasmosis = 3
Cryptococcosis = 1
Rosai Dorfman disease = 1
Sorry, no idea = 1
DISCUSSION:
The cytological diagnosis of mycobacterial infections has historically
depended on the recognition of the characteristic granulomatous or caseating
host response and the identification of acid-fast bacilli with special
stains. However, immunocompromised patients with infections may not mount
the expected response and the pathologist must have a high index of
suspicion for the presence of acid-fast microorganisms. In this particular
case a diagnosis of tuberculosis was thought of on the routine MGG slides
without special stains in the absence of granulomatous inflammation. The
organisms appeared as negative "ghostly" images of unstained, rod-shaped
structures against the deep blue background of the stain. The findings were
confirmed with Ziehl-Neelsen stain. Culture studies couldnt be done. Many
of these turn out to belong to MAC group of organisms.
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