Differential diagnosis of cutaneous and subcutaneous myxoid lesions

	sex ration (F:M)	typical age (years)	site of predilection	differential diagnosis	histopathology
Benign lesions
myxoid dermatofibroma	F>M	30-50	lower extremities	cutaneous myxoma	acanthosis, storiform pattern, peripheral sclerosis, variable factor XIIIa and SMA positivity
cutaneous focal mucinosis	F=M	20-50	face>trunk>extremities	mat be a variant of myxoid dermatofibroma or an early cutaneous myxoid cyst	loose dermal collagen, peripherally accentuated fibroblasts
cutaneous myxoid cyst	2:1	>10	fingers	probably a variant of ganglion	as cutaneous focal mucinosis, plus cyst formation
trichodiscoma	F=M	30-50	face		follicular neoplasm of sebaceous mantle zone
angiomyxoma	F=M	15-30	face (eyelids, ear)		often multiple, lobulated, vascular, +/- epithelial component, frequent perivascular neutrophils
cellular myxoma of soft tissue	F>M	25-85	extremities, usually deep but may be superficial	intramuscular myxoma, low-grade myxofibrosarcoma	cellular and vascular but lacking pleomorphism, lacks curvilinear vessels
juxtra-articular myxoma	1:3	30-50	knee	probably a low-grade variant of myxofibrosarcoma	subcutaneous, vaguely lobular, often cystic
dermal fasciitis	F<M	10-20	head & neck		well-circumscribed papule with collarette
myxoid spindle cell lipoma	F<M	45-65	neck & shoulder	myxoid liposarcoma	multilobular, adipocytes
myxoid leiomyoma	F>M	40-60	wrist		desmin variable
myxoid neurofibroma	F=M	20-30	extremities	myxoma	pointed serpentine nuclei
myxoid Schwannoma	F=M	20-30	head & neck, upper extremities	myxoid neurothekeoma	Antoni B areas, S-100 variable
myxoid chondroma	F=M	30-60	hands, feet	myxoid chondrosarcoma	nodular, hyaluronidase-resistant mucin, S-100 positive
superficial acral fibromyxoma	1:2	14-72	hands, feet	see differential	periungual, myxocollagenous, CD 34 positive
Malignant lesions
ossifying fibromyxoid tumour	F<M	40-60	distal extremities		multinodular, nested epithelioid cells, sheath of lamellar bone
myxoid dermatofibrosarcoma protuberans	F<M	40-60	lower extremities, groin		irregular outline, storiform CD 34 variable
aggressive angiomyxoma	F>M	20-50	genital, perianal, pelvic area	angiomyofibroblastoma	hyaline vessels, some with thick walls, of variable size, desmin and SMA variable
myxofibrosarcoma	F<M	50-80	lower extremity		multinodular, bizarre hyperchromatic giant cells, curvilinear vessels
low grade fibromyxoid sarcoma	F<M	20-40	extremities, retroperitoneum		alternating fibrous and myxoid areas, whorled pattern
myxoid liposarcoma	F<M	40-60	extremities, retroperitoneum		plexiform capillaries, perivascular lipoblasts
myxoid leiomyosarcoma	F=M	50-80	thigh, retroperitoneum		blunt-ended nuclei, desmin and SMA positive
botryoid rhabdomyosarcoma	F<M	0-10	head & neck		oedematous, grape-like, cambium layer, rhabdomyoblasts, myoglobin positive
extraskeletal myxoid chondrosarcoma	1:2	>35	lower extremity, juxtra-articular		strands of chondroblasts, S-100 positive
myxoid malignant melanoma	F=M	30-60	trunk>limbs	MFH, myxoid rhabdomyosarcoma, myxoid chondrosarcoma	variably positive for S-100 and HMB-45

References

Zelger, B. G., Alonje, E., Zelger, B. Myxoid dermatofibroma. Histopathology 1999;34:357-364

This page last revised 6.9.2001.