Lipomatous/Extensively Vacuolated Ependymoma with Signet-Ring Cell-Like Appearance: Analysis of a Case with Extensive Literature Review

Table 1

Lipomatous and extensively vacuolated ependymomas with signet-ring cells case list.

Case #.	Year	Author (country)	Age/gender	Location	Phrased; diagnosis	Additional histopathological features; (VÇ areas)	EMA (VÇ)	PI (VÇ)	Ultrastructural findings; (VÇ)	Associated neuroepithelial component	Follow-up
1	1994	Mierau et al. [5] (U.S.A.)	12♀	Left parietooccipital region	Signet-ring cell	Focal calcification	NR	NR	Large vacuoles with attenuated microvilli	Conventional ependymoma	NS
2			44♀	4th ventricle		Thick collagenous collars around blood vessels	NR	NR	Numerous large vacuoles lined by microvilli and cilia	NS	NS
3	1997	Hirato et al. [6] (Japan)	2♀	Left occipital lobe	Extensively vacuolated	PAS (−); alcian blue (−); oil red O (−)	Negative; (some granular or microvesicular immunopositive structures in cytoplasm or intercellular spaces)	<1%	Numerous vacuoles of different size without microvilli, some of them fused with each other, with attached ribosomes or containing granulofibrillary material simulating degenerated mitochondria	Clear cell ependymoma	Recurrence after 1 y
4	1998	Takahashi et al. [8] (Japan)	49♀	Spinal cord; (T12-L1)	Lipidized (foamy)	Densely collagenised stroma; sudan III (+)	Positive; (granular or microvesicular structures in cytoplasm and intercellular spaces)	NR	Osmiophilic fat droplets of variable size as well as large vacuoles with scarce microvilli	Conventional ependymoma	No recurrence after 6 m
5	1998	Ruchoux et al. [7] (France)	13♂	Left frontal lobe	Lipomatous	Lymphocytic clusters; oil red O (+)	Negative	<1%	Osmiophilic fat droplets with smooth margins as well as cystic vacuoles with scarce microvilli	Conventional ependymoma	No recurrence after 2 y
6			16♂	Left parietooccipital region		Few calcium foci; mucin stains (−)	NR	<1%	No	Anaplastic ependymoma	NS
7			42♀	3rd ventricle		None	NR	NR	No	Papillary ependymoma	NS
8	1999	Vajtai et al. [12] (Hungry)	64♂	Left cerebellar hemisphere	Signet-ring cell	Labyrinthine-hyalinised vessels; PAS (−)	Positive (membranous and dot-like patterns)	<1%	with scant degenerated microvilli, distended rER, coupling of tumour cells around dilated intercellular lumina	Clear cell ependymoma	Two consecutive surgeries at 8 m interval
9	2000	Sharma et al. [3] (India)	18♂	Left parietal lobe	Lipomatous	None	Negative	<20%	No	Anaplastic ependymoma	Recurrence after 2 y
10			17♂	Posterior fossa		None	Negative	<20%	No	Anaplastic ependymoma	Recurrence after 2 y
11			4♂	Right frontal lobe; (lateral ventricle-3rd ventricle)		None	Negative	NR	No	Cellular ependymoma	Recurrence after 4 y
12			35♂	4th ventricle		None	Negative	<1%	No	Conventional ependymoma	No recurrence after 1 y
13			45♂	Spinal cord; (T2-T3)		None	Negative	<1%	No	Conventional ependymoma	No recurrence after 3 y
14	2001	Chang and Finn [11] (U.S.A)	5♂	Left parietooccipital region; (lateral ventricle)	Lipomatous	Patchy calcification	Negative	NR	No	Anaplastic ependymoma	Two consecutive surgeries at 8 m interval
15	2001	Otani et al. [14] (Japan)	37♀	Spinal cord	Signet-ring cell	NA	NA	NA	NA	NA	NA
16			52♀	Spinal cord		NA	NA	NA	NA	NA	NA
17	2003	Kim et al. [13] (Japan)	59♂	Spinal cord (T3-T4)	Lipidized (foamy)	None	Positive; (microvesicular and granular patterns)	<1%	No	Clear cell ependymoma	NS
18	2005	Onaya et al. [15] (France)	51♂	Spinal cord (T6-T7)	Lipomatous	NA	NA	NA	NA	NA	NA
19	2010	Ertan et al. [9] (Turkey)	35♀	4th ventricle	Signet-ring cell	Lipofuscin, melanin, and rosenthal fibers; alcian blue (−)	Positive; (dot-like and small vesicular patterns)	<1%	No	Conventional ependymoma	NS
20	2011	Gessi et al. [4] (Germany)	40♂	Cervical	Extensively vacuolated	PAS-alcian blue (−)	Positive; (dot-like and small vesicular patterns)	NR	No	Conventional ependymoma	NS
21			54♂	Spinal cord; (C5-C6)		PAS-alcian blue (−)	Positive; (dot-like and small vesicular patterns)	NR	No	Conventional ependymoma	NS
22			59♂	Spinal cord; (C4-C5)		PAS-alcian blue (−)	Positive; (dot-like and small vesicular patterns)	NR	No	Conventional ependymoma	NS
23			30♀	4th ventricle		None	Positive; (dot-like and small vesicular patterns)	NR	No	Conventional ependymoma	NS
24			15♂	4th ventricle		PAS-alcian blue (−)	NR	NR	No	Conventional ependymoma	Recurrence after 2 y
25			54♀	3rd ventricle-4th ventricle		PAS-alcian blue (−)	Negative	NR	No	Conventional ependymoma	NS
26	2016	Gaur et al. [10] (India)	13♀	Right lateral ventricle	Lipomatous	PAS (−); alcian blue (−); oil red O (+)	Positive (membranous pattern in some cells)	<3%	Osmiophilic fat droplets	Cellular ependymoma	Recurrence after 1 y
27	2016	Present Case (Mexico)	16♂	Left frontal lobe	Lipomatous | signet-ring cell	Hyalinised vessels with conspicuous dystrophic calcification; PAS (−); alcian blue (−)	Negative	<1%	membrane-covered vacuoles of different size without microvilli or cilia but containing granulofibrillary material and not apparently related with rER.	Anaplastic ependymoma	No recurrence after 2 m
Statistical summary
Adults: 17 (62.96%), paediatric: 10 (37.03%), male: 16 (59.26%), and female 11 (40.74%)
Mean age: 32.63 y | Age range: 2 y to 64 y
Supratentorial: 11 (40.74%); lateral ventricles: 3, 3rd ventricle: 3, cerebral lobes: 6, infratentorial: 8 (29.63%); 4th ventricle: 6, cerebelar hemispheres: 1 and Spinal Chord: 9 (33.3%)
Cases with relapsing tumours: 8, relapsed & associated with anaplastic ependymoma: 3, relapsed & associated with clear cell ependymoma: 2

♂: male, ♀: female, y: years, mo: months, PI: proliferation index (MIB-1 and Ki-67), NR: not requested, NS: not specified, NA: nonavailable data,VÇ: vacuolated cells, : transmission electron microscopy, rER: rough endoplasmic reticulum, : material recovered from paraffin-embedded tissue.