Ovalocytes - Revision history

John at 12:29, 27 March 2023

2023-03-27T12:29:12Z

← Older revision		Revision as of 14:29, 27 March 2023
Line 16:		Line 16:

	<span style="font-style:italic; font-size:90%;'' >		<span style="font-style:italic; font-size:90%;'' >
	'''''Images''' Ovalocytes are regular rounded cells that are elongated. The term ovalocyte can be applied to cells where the length is greater than the width, but is not yet twice the width (at which point the cell is more often referred to as an elliptocyte). This form arises in many different contexts (~~see causes~~).		'''''Images''' Ovalocytes are regular rounded cells that are elongated. The term ovalocyte can be applied to cells where the length is greater than the width, but is not yet twice the width (at which point the cell is more often referred to as an elliptocyte). This form arises in many different contexts although the most familiar is with megalobastic anaemias (look for related features such as hypersegmented neutrophils).
	</span>		</span>

John at 12:26, 27 March 2023

2023-03-27T12:26:41Z

← Older revision		Revision as of 14:26, 27 March 2023
Line 10:		Line 10:

	<gallery mode="nolines" widths="240px" heights="240px" border="1px" >		<gallery mode="nolines" widths="240px" heights="240px" border="1px" >
	File:~~Ova1~~.png\|link={{filepath:Ova1.png}}		File:Ova1A.png\|link={{filepath:Ova1.png}}
	File:Ova2.jpg\|link={{filepath:Ova2.jpg}}		File:Ova2.jpg\|link={{filepath:Ova2.jpg}}
	</gallery>		</gallery>

John at 11:45, 22 March 2023

2023-03-22T11:45:32Z

← Older revision		Revision as of 13:45, 22 March 2023
Line 1:		Line 1:



	'''Derivation:''' '' latin ovum - egg ''		'''Derivation:''' '' latin ovum - egg ''

John at 14:46, 21 March 2023

2023-03-21T14:46:12Z

← Older revision		Revision as of 16:46, 21 March 2023
Line 73:		Line 73:
	'''Clinical Image 1:''' A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis		'''Clinical Image 1:''' A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis
	</span>		</span>



Line 79:		Line 80:
	</gallery>		</gallery>

	<span style="font-size:90%">
			<span style="font-style:italic; font-size:90%;'' >
	'''Clinical Image 2:''' Multiple oval-shaped cells in the context of general macrocytosis (compare with the nucleus of the included normal small lymphocyte). Image: B12 deficiency		'''Clinical Image 2:''' Multiple oval-shaped cells in the context of general macrocytosis (compare with the nucleus of the included normal small lymphocyte). Image: B12 deficiency



	<gallery widths="250px" heights="250px" >		<gallery widths="250px" heights="250px" >
Line 86:		Line 90:
	</gallery>		</gallery>

	<span style="font-size:90%">
			<span style="font-style:italic; font-size:90%;'' >
	'''Clinical Image 3:''' More severe megaloblastic anaemia with very prominent large macrocytic cells. In this case the overall fragility of the developing abnormal erythrocytes has also produced small fragmented cells that cause an apparent reduction in the overall MCV. Image: B12 deficiency		'''Clinical Image 3:''' More severe megaloblastic anaemia with very prominent large macrocytic cells. In this case the overall fragility of the developing abnormal erythrocytes has also produced small fragmented cells that cause an apparent reduction in the overall MCV. Image: B12 deficiency
	----		----

John at 14:44, 21 March 2023

2023-03-21T14:44:31Z

← Older revision		Revision as of 16:44, 21 March 2023
Line 53:		Line 53:
	\|Ovalocytes may form as the first stage in elliptocyte formation - consider whether the cells are simply early elliptocytes		\|Ovalocytes may form as the first stage in elliptocyte formation - consider whether the cells are simply early elliptocytes
	\|-		\|-
	\|Ovalocytes and elliptocytes ~~may be infrequent forms~~ in a range of disorders, in those conditions it is ~~probably~~ best to focus on the dominant features of the film		\|Ovalocytes and elliptocytes are present in low number in a range of disorders, in those conditions it is best to focus on the dominant features of the film
	\|-		\|-
	\|}		\|}
Line 69:		Line 69:
	</gallery>		</gallery>

	<span style="font-size:90%">
			<span style="font-style:italic; font-size:90%;'' >
	'''Clinical Image 1:''' A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis		'''Clinical Image 1:''' A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis
	</span>		</span>


	<gallery widths="250px" heights="250px" >		<gallery widths="250px" heights="250px" >

John at 14:42, 21 March 2023

2023-03-21T14:42:42Z

← Older revision		Revision as of 16:42, 21 March 2023
Line 12:		Line 12:


	[[File:Ova1.png\|~~180px\|~~\|link=]]		<gallery mode="nolines" widths="240px" heights="240px" border="1px" >
			File:Ova1.png\|link={{filepath:Ova1.png}}
			File:Ova2.jpg\|link={{filepath:Ova2.jpg}}
			</gallery>


	<span style="font-size:90%">		<span style="font-style:italic; font-size:90%;'' >
	'''''~~Image 1~~'''~~Image 1 An ovalocyte is a red cell which is~~ regular ~~and~~ rounded ~~but is also~~ elongated. The term ovalocyte can be applied to cells where the length is greater than the width, but is not yet twice the width (at which point the cell is more often referred to as an elliptocyte)		'''''Images''' Ovalocytes are regular rounded cells that are elongated. The term ovalocyte can be applied to cells where the length is greater than the width, but is not yet twice the width (at which point the cell is more often referred to as an elliptocyte). This form arises in many different contexts (see causes).
	~~Image 2 There are~~ many different contexts ~~for ovalocytes~~ (see causes~~). In this case an enlarged and ovoid cell is shown together with a hypersegmented neutrophil a feature of megaloblastic states (most commonly vitamin B12 or folate deficiency~~).
	</span>		</span>

Line 38:		Line 40:

	<div style="width: 95%; overflow: auto; border: 1px solid navy; font-size:100%">		<div style="width: 95%; overflow: auto; border: 1px solid navy; font-size:100%">
			{\| class="wikitable" style="color:black; background-color:#ffffff;" cellpadding="15"
	{\| class="wikitable"
	!colspan="1"\|'''INHERITED DEFECTS'''		!colspan="1"\|'''INHERITED DEFECTS'''
	\|-		\|-

John at 13:35, 20 March 2023

2023-03-20T13:35:17Z

← Older revision		Revision as of 15:35, 20 March 2023
Line 40:		Line 40:

	{\| class="wikitable"		{\| class="wikitable"
	!colspan="1"\|'''~~Physiological or artefact~~'''		!colspan="1"\|'''INHERITED DEFECTS'''
	\|-		\|-
	\|1. ~~Reticulocytes are larger than mature erythrocytes so MCV is higher~~		\|S.E.Asian Ovalocytosis A specific disorder that results from structural and functional defects of the band 3 protein causing ovalocytes with a stomatocytic appearance.
	\|-		\|-
	\|~~2. Red cell agglutination may result in apparent elevation of overall mean cell volume detected by automated analysers~~		!colspan="1"\|'''MEGALOBLASTIC STATES'''
	\|-		\|-
	~~!colspan="1"~~\|~~'''Impaired cell division''' (nutritional or metabolic)~~		\|Look for characteristic oval macrocytes in the context of typical hypersegmented neutrophils and other features of these disorders
	\|-		\|-
	\|~~1. Vitamin B12 deficiency (most commonly due to impaired absorption)~~		!colspan="1"\|'''AS PART OF A SPECTRUM OF ABNORMAL CELLS'''
	\|-		\|-
	\|~~2. Folic acid deficiency (most commonly dietary deficiency)~~		\|Ovalocytes may form as the first stage in elliptocyte formation - consider whether the cells are simply early elliptocytes
	\|-		\|-
	~~!colspan="1"~~\|~~'''Impaired cell division''' (drug)~~		\|Ovalocytes and elliptocytes may be infrequent forms in a range of disorders, in those conditions it is probably best to focus on the dominant features of the film
	\|-		\|-
	~~\|1. Cytotoxic e.g. hydroxycarbamide~~
	\|-
	~~\|2. Immunosuppressive e.g. azathioprine~~
	\|-
	~~!colspan="1"\|'''Defective cell formation'''~~
	\|-
	~~\|1. Most frequently myelodysplasia (also seen in congenital dyserythropoiesis, aplastic anaemia or post stem-cell transplant)~~
	\|-
	~~!colspan="1"\|'''Other causes'''~~
	\|-
	~~\|1. Alcohol and liver disease: excess cell membrane lipid~~
	\|-
	~~\|2. Hypothyroidism. Likely caused by reduced cell division~~
	\|-
	~~\|3. Drugs and medication, causing macrocytosis through various mechanisms~~
	\|}		\|}
	</div>		</div>
Line 108:		Line 93:

	----		----


	~~Causes~~
	~~INHERITED DEFECTS~~
	~~S.E.Asian Ovalocytosis A specific disorder that results from structural and functional defects of the band 3 protein causing ovalocytes with a stomatocytic appearance.\~~
	~~MEGALOBLASTIC STATES~~
	~~Look for characteristic oval macrocytes in the context of typical hypersegmented neutrophils and other features of these disorders~~
	~~AS PART OF A SPECTRUM OF ABNORMAL CELLS~~
	~~Ovalocytes may form as the first stage in elliptocyte formation â€“ consider whether the cells are simply early elliptocytes~~
	~~Ovalocytes and elliptocytes may be infrequent forms in a range of disorders, in those conditions it is probably best to focus on the dominant features of the film~~

John at 13:15, 20 March 2023

2023-03-20T13:15:07Z

← Older revision		Revision as of 15:15, 20 March 2023
Line 80:		Line 80:

	<gallery widths="250px" heights="250px" >		<gallery widths="250px" heights="250px" >
	File:~~Mac2~~.jpg\|link={{filepath:~~Mac2~~.jpg}}		File:Ova3.jpg\|link={{filepath:Ova3.jpg}}
	</gallery>		</gallery>

	<span style="font-size:90%">		<span style="font-size:90%">
	'''''Clinical Image 1:''' ~~The nucleus~~ of ~~the small lymphocyte provides a reference to judge erythrocyte size – this reveals that almost all the erythrocytes shown here are macrocytes~~. Note ~~here that~~ the ~~majority have an oval shape “oval macrocytes”. An obvious exception being~~ the ~~truly huge polychromatic erythrocyte (upper right corner) which has a round shape~~. ~~Clinical disorder~~: ~~folate deficiency''~~		'''Clinical Image 1:''' A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis
	</span>		</span>

	<gallery widths="250px" heights="250px" >		<gallery widths="250px" heights="250px" >
	File:~~Mac3~~.jpg\|link={{filepath:~~Mac3~~.jpg}}		File:Ova4.jpg\|link={{filepath:Ova4.jpg}}
	</gallery>		</gallery>

	<span style="font-size:90%">		<span style="font-size:90%">
	'''''Clinical Image 2:''' ~~This film has a more varied cell size with some very large~~ cells~~, but others~~ of ~~normal or small size. Nonetheless~~ the ~~macrocytes are highly significant. In this case~~ the ~~additional hypersegmented neutrophil indicates the underlying megaloblastic state – some~~ small ~~or even fragmented red cells can occur in severe B12 or folate deficiency reflecting fragile red cells~~. ~~Clinical disorder~~: ~~folate~~ deficiency''		'''Clinical Image 2:''' Multiple oval-shaped cells in the context of general macrocytosis (compare with the nucleus of the included normal small lymphocyte). Image: B12 deficiency

			<gallery widths="250px" heights="250px" >
			File:Ova5.jpg\|link={{filepath:Ova5.jpg}}
			</gallery>

			<span style="font-size:90%">
			'''Clinical Image 3:''' More severe megaloblastic anaemia with very prominent large macrocytic cells. In this case the overall fragility of the developing abnormal erythrocytes has also produced small fragmented cells that cause an apparent reduction in the overall MCV. Image: B12 deficiency
	----		----

Line 100:		Line 105:
	'''Pathobiology'''		'''Pathobiology'''

	~~Where cell division is impaired the maturing erythrocytes undergo fewer cycles~~ of ~~division and so emerge from~~ the ~~marrow as larger cells~~. ~~We tend to associate severe macrocytosis~~ with ~~nutritional deficiency affecting~~ cell ~~division (vitamin B12 or folate deficiency); less severe macrocytosis may result from metabolic effects on cell division (e~~.g. ~~hypothyroidism or occasionally chronic disease), or due to intrinsic impaired cell maturation (myelodysplasia)~~. ~~However, macrocytosis~~ may ~~also arise as a result~~ of ~~increased membrane lipid e.g. in liver disease (most particularly alcoholic liver disease, Zeives Syndrome, or cirrhosis) in this case~~ the ~~macrocytes can be very large~~.		Ovalocytes in inherited or dyserthropoietic disorders arise by similar mechanism to elliptocytes having an unstable cytoskeleton that allows them to be deformed by shear-stress; in this case there are a range of forms with different severity. In some instances however they may arise because of a particular defect - the classic ovalocyte arises in S.E.Asian ovalocytosis where the transmembrane protein "band 3" is defective at its binding site with other elements of the erythrocyte cytoskeleton - causing a relatively rigid cell structure. The defect is widespread in S.E.Asian populations and may provide resistance to invasion of the erythrocyte by malarial parasites.

	----		----


	Causes		Causes
	INHERITED DEFECTS		INHERITED DEFECTS
Line 111:		Line 118:
	Ovalocytes may form as the first stage in elliptocyte formation â€“ consider whether the cells are simply early elliptocytes		Ovalocytes may form as the first stage in elliptocyte formation â€“ consider whether the cells are simply early elliptocytes
	Ovalocytes and elliptocytes may be infrequent forms in a range of disorders, in those conditions it is probably best to focus on the dominant features of the film		Ovalocytes and elliptocytes may be infrequent forms in a range of disorders, in those conditions it is probably best to focus on the dominant features of the film

	~~Clinical Image 1 A large ovalocyte within the context of normally sized red cells. Note also the slit like central pallor of many of the cells. Image: S.E.Asian ovalocytosis~~
	~~Clinical Image 2 Multiple oval-shaped cells in the context of general macrocytosis (compare with the nucleus of the included normal small lymphocyte). Image: B12 deficiency~~
	Clinical Image 3 More severe megaloblastic anaemia with very prominent large macrocytic cells. In this case the overall fragility of the developing abnormal erythrocytes has also produced small fragmented cells that cause an apparent reduction in the overall MCV. Image: B12 deficiency

	~~Pathobiology~~
	Ovalocytes in inherited or dyserthropoietic disorders arise by similar mechanism to elliptocytes having an unstable cytoskeleton that allows them to be deformed by shear-stress; in this case there are a range of forms with different severity. In some instances however they may arise because of a particular defect - the classic ovalocyte arises in S.E.Asian ovalocytosis where the transmembrane protein "band 3" is defective at its binding site with other elements of the erythrocyte cytoskeleton - causing a relatively rigid cell structure. The defect is widespread in S.E.Asian populations and may provide resistance to invasion of the erythrocyte by malarial parasites.

John at 13:11, 20 March 2023

2023-03-20T13:11:37Z

← Older revision		Revision as of 15:11, 20 March 2023
Line 31:		Line 31:
	'''Pitfalls'''		'''Pitfalls'''

	~~Where cell fragments are present in addition to macrocytes~~ (~~this may occur for example in severe vitamin B12~~ or ~~folate deficiency~~) ~~this~~ may ~~reduce the overall mean cell volume (MCV) given by automated counters even when the non-fragmented cells are large, this can~~ be ~~a particular issue in megaloblastic anaemia~~. ~~Also remember~~ that ~~reticulocytes may be 20-25% larger than normal red cells, so polychromatic cells should not be confused with macrocytes.~~		Ovalocytes should be distinguished from other elongated forms (elliptocytes or pencil cells) and can arise as part of the spectrum of elliptocytes where they may be better considered as part of that context. Particularly look for those forms that have particular diagnostic significance (see below)


	----		----
Line 104:		Line 103:

	----		----






	Pitfalls Ovalocytes should be distinguished from other elongated forms (elliptocytes or pencil cells) and can arise as part of the spectrum of elliptocytes where they may be better considered as part of that context. Particularly look for those forms that have particular diagnostic significance (see below)
	Causes		Causes
	INHERITED DEFECTS		INHERITED DEFECTS

John at 13:11, 20 March 2023

2023-03-20T13:11:02Z

← Older revision		Revision as of 15:11, 20 March 2023
Line 25:		Line 25:
	'''Significance'''		'''Significance'''

	~~Morphologically detectable macrocytosis will generally have an underlying cause~~. ~~Therefore attention is required to identify this - morphological evidence of any accompanying disease should actively be sought~~. ~~Most frequently~~ these ~~causes~~ are ~~B12~~ or ~~folate deficiency,~~ myelodysplasia, ~~or liver disease~~.		For ovalocytes that are large, consider: oval macrocytes of megaloblastic states, and the very large (stomatocytic) ovalocytes that are part of of S.E.Asian ovalocytosis. In these cases the additional diagnostic blood appearances are crucial. Where ovalocytes are not enlarged they generally form part of a spectrum of cells e.g. in hereditary elliptocytosis or as part of the dyserythropoietic spectrum in a range of disorders (myelodysplasia, iron deficiency etc).


Line 109:		Line 109:


	Significance For ovalocytes that are large, consider: oval macrocytes of megaloblastic states, and the very large (stomatocytic) ovalocytes that are part of of S.E.Asian ovalocytosis. In these cases the additional diagnostic blood appearances are crucial. Where ovalocytes are not enlarged they generally form part of a spectrum of cells e.g. in hereditary elliptocytosis or as part of the dyserythropoietic spectrum in a range of disorders (myelodysplasia, iron deficiency etc).
	Pitfalls Ovalocytes should be distinguished from other elongated forms (elliptocytes or pencil cells) and can arise as part of the spectrum of elliptocytes where they may be better considered as part of that context. Particularly look for those forms that have particular diagnostic significance (see below)		Pitfalls Ovalocytes should be distinguished from other elongated forms (elliptocytes or pencil cells) and can arise as part of the spectrum of elliptocytes where they may be better considered as part of that context. Particularly look for those forms that have particular diagnostic significance (see below)
	Causes		Causes