Abdominal fat pad aspiration biopsy for tissue confirmation of systemic amyloidosis: Specificity, positive predictive value, and diagnostic pitfalls

Abstract

Abdominal fat pad fine‐needle aspiration biopsy (FNAB) is considered the method of choice for confirmation of systemic amyloidosis. Due to our impression that positive results are rare in our FNA service, we retrospectively analyzed our results. Forty‐five samples collected from 45 patients over 3 yr were reviewed. Of the 7 patients with positive Congo red‐stained FNAB specimens, all 7 (100%) had documented amyloidosis. Of the 33 patients with negative Congo red fat samples, 28 (85%) were disease‐free. Of the 5 patients with inadequate samples, 2 (40%) were later diagnosed with disease. We demonstrate excellent specificity (100%). The positive predictive value, documented in only a few previous studies, is likewise excellent (100%). Sensitivity is low (58%) and inadequacy is high (11%). Improvement in technique, such as concurrent cell block preparation, may help avoid inadequate specimens. Difficulties in confirming amyloidosis also include interpretation of the Congo red stain (pale‐stained amyloid fibrils and collagen birefringence). Diagn. Cytopathol. 2001;24:181–185. © 2001 Wiley‐Liss, Inc.

Diagnosis of Amyloidosis

“…The sensitivity reported range from 55-75% and specificity is over than 90% [2,6]. Guy and Jones, analyzing the performance of the abdominal fat pad aspiration in 45 patients with systemic amyloidosis found sensitivity of 58%, specificity of 100%, positive predictive value of 100% and negative predictive value of 85%, confirming the accuracy of the methodology [7].…”

A Novel Tool for Detecting Amyloid Deposits in Systemic Amyloidosis In Vitro and In Vivo

“…In systemic amyloidosis, such as familial amyloidotic polyneuropathy (FAP), AA amyloidosis, AL amyloidosis, and dialysis-related amyloidosis (DRA), biopsy samples are often obtained from the gastrointestinal tract and abdominal fat to make the diagnosis (Guy and Jones, 2001;Kaplan et al, 1999;Masouye, 1997) because amyloid deposits are usually found in these tissues at the early stage of the disease. However, in certain cases it is sometimes difficult to make the diagnosis using only the biopsy samples, because the pattern of amyloid deposition in the body varies in each individual (Ishihara et al, 1989).…”

“…In systemic amyloidoses such as FAP, AA, AL, and DRA, most of the diagnostic methods are invasive (Guy and Jones, 2001;Ishihara et al, 1989;Kaplan et al, 1999;Masouye, 1997), with biopsy of the gastrointestinal system, abdominal fat, or sural nerves often used. However, amyloid deposition is not uniform in all forms of systemic amyloidosis (Ishihara et al, 1989;Tan and Pepys, 1994).…”

Prognosztikai tényezők könnyűlánc-amyloidosisban

“…Ezt egy 450 beteg bevonásával végzett vizsgálat során bizonyították, amelynek eredménye alapján, kizá-rólagos perifériás idegérintettség mellett a zsírszövetben amyloidlerakódás egyetlen esetben sem volt igazolható [14]. Egy másik tanulmány szerint a szubkután hasi zsír-szövet-aspiráció specifi citása és pozitív prediktív értéke szisztémás amyloidosisban 100%, ám szenzitivitása (58%) elmarad a kívánt szinttől [15]. Egy további közlemény arról számol be, hogy a zsírszövet-aspiráció szenzitivitása 93%-ra növelhető, amennyiben legalább három kenet alapos vizsgálatát végezzük el [16].…”