79) Cysts скачать в хорошем качестве

79) Cysts

Cysts - A soft fluctuant swelling containing fluid in a sac lined by epithelium or endothelium is called a ‘cyst’. The word ‘cyst’ is derived from a greek word meaning ‘ bladder’. Classification – Two types of classification of cysts are known in surgical practice. I. First type – 1. True cysts and 2. False cysts ( Pseudocysts). 1. True cysts - are lined by epithelium or endothelium, though if infected it may be lined by granulation tissue. The fluid of a true cyst may be either of the following two varieties – (i) It is usually serous or mucoid and varies in colour from almost colourless to brown-staining due to presence of altered blood. Cholesterol crystals are often present in the fluid. (ii) The content may be porridge or toothpaste-like due to accumulation of desquamated epithelium within the secretion. Such content is usually found in dermoid, epidermoid, brachial cysts and sebaceous cysts. 2. False Cysts or Pseudocysts- These may be of the following types :- (i) Exudation cysts – Such cysts develop from exudation of fluid and are limited in anatomical spaces e.g. pseudopancreatic cysts ( encysted collection of fluid in the lesser sac ) , fluid of tuberculous peritonitis lined by adherent coils of intestine, vaginal hydrocele, bursa. (ii) Degeneration cysts – Such cysts develop as degeneration in the centre of a malignant tumour due to haemorrhage or ischaemic necrosis or colliquative necrosis. Apoplectic cyst is an example of this type. II. The second type of classification - congenital or acquired 1. Congenital cysts are of following varieties :- (a) Sequestration dermoid – This type of cyst develops at the line of closure of embryonic clefts due to burial of dermal cells in this fusion line. The usual sites are in the midline of the body (particularly in the neck), at the outer angle of the orbit (angular dermoid), in the upper part of the anterior triangle of the neck ( which is known as brachial cyst, developed due to persistence of precervical pouch after fusion of the brachial clefts.) (b) Tubulo-embyonic or tubulo-dermoid cyst – Such cysts develop in the tract of an ectoderm tube e.g. thyroglossal cyst from the thyroglossal duct. (c) Cysts of embryonic remnants – Certain cysts develop from embryonic tubules or ducts which normally disappear. The examples of such cysts are of the urachus and vitello- intestinal duct; hydatid of Morgagni from remnants of paramesonephric ducts; cyst from the remains of mesonephric duct ( Wolffian body) which is known as organ of Giraldes. 2. Acquired cysts – The various types of acquired cysts are as follows :- (a) Retention cysts – Such cyst develops due to retention of secretion of a gland due to obstruction of its duct. The common examples are sebaceous cysts, cysts of the breasts, mucous cysts of the lips and cheeks, pancreatic cyst, parotid cyst, Bartholin’s cyst etc. (b) Distention cyst – Such cyst develops from distension of normal acini or follicles of a gland e.g. thyroid cyst, ovarian cyst. Lymphatic cyst and cystic hygromas are also included in this variety as such cysts also develop due to distension of lymph sacs or lymphatics. (c) Exudation cyst –This type of cyst develops due to exudation of fluid into an anatomical space already lined by endothelium e.g. vaginal hydrocele, bursa and pseudo-pancreatic cyst. It is noteworthy that these are usually false cysts according to the previous classification. (d) Degeneration cyst- These are degeneration cysts mentioned under the group of false cysts. (e) Cystic tumours e.g. dermoid cyst of the ovary, cystadenomas of the ovary, cystadenoma of the breast etc. (f) Implantation dermoids – Such cysts develop when squamous epithelium of the skin is driven in by a penetrating wound. Such cysts are usually seen in the finger, hand or sole of the foot. (g) Traumatic cyst – Sometimes haematoma within the muscles, fascia or subcutaneous tissue may resolve into a cyst. Such cyst contains straw-or brown-coloured fluid containing cholesterol crystrals and is usually lined by endothelium. (h) Parasitic cysts – In this group the commonest is hydatid cyst developed from infestation of Tinea Echinococcus. Such cysts are mostly seen in the liver or lung though they may be seen in other parts of the body as well. Besides hydatid cyst other cysts in this group are – cysticercosis due to infestation of tinea solium. The cysticercus is the intermediate stage of the parasite. This is mainly a disease of the pig, though human beings are rarely affected. Clinical features of a cyst – (i) Duration of the swelling (ii) How did the swelling appear (iii) Pain (iv) Growth of cyst Physical examination – Inspection – (i) Site – (ii) Number - iii) Surface and margin PALPATION ---- i) Surface and margin ii) Consistency iii) Fluctuation iv) Fluid thrill v) Translucency Complications - i) Infection ii) Haemorrhage iii) Torsion iv) Calcification