Home Chapter Home Jobs Conferences Fellowships Books
Soft Tissue Tumors Part 3 - Muscle, Vascular, Nerve, Other
Other
Myospherulosis
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Revised: 6 April 2010, last major update April 2010
Copyright: (c) 2010, PathologyOutlines.com, Inc.
Definition
=========================================================================
● Iatrogenic benign mass composed of fungi-like spherules composed of erythrocytes damaged by endogenous and exogenous fat
Terminology
=========================================================================
● Also called subcutaneous spherulocystic disease (Trans R Soc Trop Med Hyg 1971;65:182)
History / etiology
=========================================================================
● First described by McClatchie (E Afr Med J 1969;46:625), who reported 7 patients from Kenya with unusual soft tissue nodules in the arm, legs and subcutaneous tissue of the buttock
● Called myospherulosis due to the involvement of skeletal muscle in some patients (Am J Clin Pathol 1969;51:699)
● Five patients were subsequently reported by Hutt in Uganda, who termed the entity subcutaneous spherulocystic disease (Trans R Soc Trop Med Hyg 1971;65:182)
● Initially these structures were thought to be a fungus, but the usual stains for fungi were negative
● In 1977, Kyriakos (Am J Clin Pathol 1977;67:118) reported non-African cases in the paranasal sinuses, nasal cavity and middle ear; most patients had undergone surgery and the surgical wound was packed with gauze impregnated with petrolatum and tetracycline ointment, which suggested an iatrogenic etiology
● This was demonstrated by De Schriver and Kyriakos, who induced similar lesions in experimental animals (Am J Pathol 1977;87:33)
● The pathogenesis of the disease was confirmed by Rosai (Am J Clin Pathol 1978;69:475), and Wheeler (Arch Otolaryngol 1980;106:272), who demonstrated that the spherules were erythrocytes damaged by endogenous and exogenous fat
● The disease was reproduced by incubating human red blood cells with tetracycline ointment, lanolin, petrolatum and liquefied human fat.
● Travis (Arch Pathol Lab Med 1986;110:763) and Shimada (Am J Surg Pathol 1988;12:427) confirmed the presence of damaged erythrocytes by immunostaining for hemoglobin
● Kakizaki (Am J Clin Pathol 1993;99:249) demonstrated that the wall of the spherules was due to the physical emulsion phenomenon that occurs between lipid-containing materials and blood
● The damaged erythrocytes are enclosed by a lipid membrane and later phagocytosed by histiocytes as part of the lipogranulomatous reaction that takes place in adipose tissue
Etiology
=========================================================================
● Due to erythrocyte damage from endogenous and exogenous fat
● Also due to endogenous membranocystic degeneration of fat that occurs in lupus erythematosus and in membranous lipodystrophy with dermal atrophy due to local application of steroid ointment (Arch Dermatol 1991;127:88)
● In the gluteal region, this entity is described in relation to old injections of petrolatum based hormones and penicillin (Diagn Cytopathol 1988;4:137, J Am Acad Dermatol 1989;21:400)
Clinical
=========================================================================
● May occur with aspergillosis of the maxillary sinus (Oral Sur Oral Med Oral Pathol 1987;63:582, Arch Pathol Lab Med 2005;129:e84)
Treatment and prognosis
=========================================================================
● Benign process; no treatment needed other than for symptomatic relief
Case reports
=========================================================================
● 39 year old man with large buttock tumor (Case of Week #173)
Gross description
=========================================================================
● Large saccular cyst-like lesion, surrounded by fat
● May contain oily substance with a yellow color
Gross images
=========================================================================
Microscopic description
=========================================================================
● Cyst composed of spherules which are damaged erythrocytes
● Wall of the cyst made of fibrous tissue, accompanied by a lipogranulomatous reaction
● Many eosinophilic spherules containing red blood cells are within histiocytes lining the cyst wall
● Some larger spherules resemble a bag of marbles
● Dermal nodules are cystic cavities with a fibrous wall lined by histiocytes and multinucleated foreign-body giant cells, with lipogranulomatous inflammation in the adipose tissue adjacent to the cavities
Micro images
Various images
Negative stains
=========================================================================
● PAS for fungi, GMS
End of Soft Tissue Tumors Part 3 > Other > Myospherulosis
This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must also be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.
All information on this website is protected by Copyright, (c) 2001-2009, PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions.