Page 297 - Textbook of Pathology, 6th Edition

vi) ABDOMINAL FAT ASPIRATION. FNA of the para- E. PRECAUTIONS AND CONTRAINDICATIONS OF FNAC 281
umbilical abdominal adipose tissue is currently accepted While FNAC is generally a safe procedure, precautions have
method for diagnosis of secondary systemic amyloidosis. to be taken when aspiration is contemplated of some sites
Amyloid is demonstrated as rings around fat cells by the under certain circumstances:
conventional Congo red staining (congophilia) and apple-
green birefringence when viewed under polarising 1. Bleeding disorders. Thrombocytopenia per se is not a CHAPTER 11
microscopy. contraindication to FNAC. In patients with coagulopathies
such as haemophilia, aspiration of joint spaces, chest and
Radiological Imaging Aids for FNAC abdominal viscera is contraindicated; superficial lesions may
be aspirated and pressure applied to the puncture site for at
Non-palpable lesions require some form of localisation by least 5 minutes following the procedure.
radiological aids for FNAC to be carried out. Plain X-ray films
are usually adequate for lesions within bones and for some 2. Liver. Estimation of prothrombin time is an essential pre-
lesions within the chest. FNAC of the chest may also be requisite for aspiration of the liver. FNAC is not advisable if
attempted under image amplified fluoroscopy which allows prothrombin index (PTI) is less than 80%. Obstructive
visualisation of needle placement on the television monitor. jaundice is a relative contraindication for FNAC on account
Computerised tomographic-(CT) guidance is also used for lesions of the risk of bile peritonitis.
within the chest and abdomen. The most versatile 3. Lung. FNAC of the lung should not be undertaken in Basic Diagnostic Cytology
radiological aid is ultrasonographic (US)-guidance which allows elderly patients with emphysema or pulmonary hyper-
direct visualisation of needle placement in real time and is tension because of the enhanced risk of pneumothorax and
free from radiation hazards. It is an extremely valuable aid haemoptysis respectively.
for FNAC of thyroid nodules, soft tissue masses, intra-abdo-
minal lesions and for intrathoracic lesions which abut the 4. Pancreas. FNAC is contraindicated in acute pancreatitis
chest wall, but is of no help in deep intrathoracic lesions or as it aggravates the inflammatory process.
in bony lesions.
5. Prostate. Transrectal aspiration in acute prostatitis may
cause bacteraemia/septicaemia and is contraindicated.
D. COMPLICATIONS AND HAZARDS OF FNAC
6. Testis. Aspiration is extremely painful in acute
FNAC is associated with relatively few complications. epididymo-orchitis and should be deferred till such time the
Possible hazards and more commonly encountered acute inflammatory process subsides. The patient is treated
complications are as follows:
with anti-inflammatory agents and antibiotics and FNAC
1. Haematomas. Bleeding from the puncture site and undertaken at a later date.
haematoma formation are the commonest complications of 7. Adrenal. FNAC of a suspected pheochromocytoma is
the procedure, particularly in the breast and the thyroid. Firm inadvisable as it may sometimes provoke extreme fluctua-
finger pressure for 2 to 3 minutes immediately after the tions in blood pressure.
procedure greatly reduces the frequency of these
complications. F. CYTOLOGIC DIAGNOSIS

2. Infection. Introduction of infection is not a significant The cytopathologist can render a preliminary diagnosis
hazard; even transabdominal aspiration does not result in within one hour after the FNAC procedure when urgently
peritoneal contamination despite puncture of bowel walls. required. Basic cytologic features in FNAC are similar to
Transrectal aspiration in cases of acute prostatitis may, those in histopathology but smear cytology depends upon
however, result in bacteraemia and septicaemia. the technique for smear and stains employed. Emphasis in
FNA cytology is on pattern recognition or arrangement of
3. Pneumothorax. Transcutaneous aspiration of the lung cells, nuclear and cytoplasmic features of individual cells or
causes pneumothorax in about 20% of cases; most resolve groups of cells, and comment on the background
spontaneously although intercostal intubation may be morphology.
required in some instances. Transient haemoptysis may also Understandably, it is beyond the scope of this book to
be associated with lung aspiration.
delve into morphological details of various lesions which can
4. Dissemination of tumour. Generalised dissemination of be sampled by FNAC; interested readers in this subject are
malignant cells via lymphatics and blood vessels following referred to the specialised texts listed at the end of the book.
FNAC is a theoretical possibility but no definite instances However, a few common and classical examples of FNAC
have been recorded. Local dissemination by seeding of applications in lymph node (tuberculous lymphadenitis,
malignant cells along the needle tract is a rare complication Fig. 11.13), thyroid (follicular neoplasm, Fig. 11.14), breast
and has been reported in cancers of the lung, prostate and (fibroadenoma and infiltrating carcinoma, Figs. 11.15 and
pancreas. Aspiration of malignant ovarian cysts may result 11.16), abdominal fat (for amyloid, Fig. 11.17) and cell-block
in release of cyst contents into the peritoneal cavity with preparation along with immunocytochemistry (Fig. 11.18)
peritoneal implants. are illustrated.