Subcutaneous fat necrosis of the newborn is a rare, benign, self-limited hypodermatitis

that affects full-term or postmature newborn with history of perinatal

stress such as hypoxia, hypothermia or local pressure trauma. The main lesions

appear as subucateneous nodules in adipose tissue.

We present a case of a three-week old newborn born in spontaneous delivery in the

40Hbd in poor general condition (inborn pneumonia and perinatal hypoxia) which

was admitted to the hospital due to subcutaneous tissue induration and skin discoloration

above the lesion. The skin ultrasound examination showed foci of homogeneously

hyperechogenic subcutaneous tissue thickened up to 6 mm. Further

examinations did not reveal any abnormalities besides the slightly increased calcium

concentration (1,69 mmol/l with normal range of 1,2 mmo/l). In order to diagnose

the condition a tissue sample was collected. The histological examination

revealed panniculitis with infiltration with mononuclear cells, e.g. macrophages as

well as multinucleated giant cells with radial arrangement of needles-shaped clefts

in cytoplasm. After treatment with corticosteroids resolution of all the lesions was

noted

Bowszyc-Dmochowska, Monika

Maciejewska, Joanna

Marszałek, Andrzej

Prokurat, Andrzej

Polish Journal of Pathology

English

Subcutaneous fat necrosis of the newborn is a rare, benign, self-limited hypodermatitis
that affects full-term or postmature newborn with history of perinatal
stress such as hypoxia, hypothermia or local pressure trauma. The main lesions
appear as subucateneous nodules in adipose tissue.
We present a case of a three-week old newborn born in spontaneous delivery in the
40Hbd in poor general condition (inborn pneumonia and perinatal hypoxia) which
was admitted to the hospital due to subcutaneous tissue induration and skin discoloration
above the lesion. The skin ultrasound examination showed foci of homogeneously
hyperechogenic subcutaneous tissue thickened up to 6 mm. Further
examinations did not reveal any abnormalities besides the slightly increased calcium
concentration (1,69 mmol/l with normal range of 1,2 mmo/l). In order to diagnose
the condition a tissue sample was collected. The histological examination
revealed panniculitis with infiltration with mononuclear cells, e.g. macrophages as
well as multinucleated giant cells with radial arrangement of needles-shaped clefts
in cytoplasm. After treatment with corticosteroids resolution of all the lesions was
noted

Jagiellonian Univeristy Repository

240SUBCUTANEOUS FAT NECROSIS OF THE NEWBORN – A CASEREPORT AND REVIEW OF LITERATUREANDRZEJ MARSZAŁEK1,2, JOANNA MACIEJEWSKA1, MONIKA BOWSZYC-DMOCHOWSKA3, ANDRZEJ PROKURAT41Chair and Department of Clinical Pathomorphology, Collegium Medicum in Bydgoszcz, Nicolai Copernici University in Toruń2Chair and Department of Clinical Pathomorphology, Poznań University of Medical Sciences3Skin Histopathology and Immunopathology Laboratory Chair of Dermatology, Poznań University of Medical Sciences4Clinic of Children’s Surgery, University Children’s Hospital in KrakówSubcutaneous fat necrosis of the newborn is a rare, benign, self-limited hypoder-matitis that affects full-term or postmature newborn with history of perinatalstress such as hypoxia, hypothermia or local pressure trauma. The main lesionsappear as subucateneous nodules in adipose tissue.We present a case of a three-week old newborn born in spontaneous delivery in the40Hbd in poor general condition (inborn pneumonia and perinatal hypoxia) whichwas admitted to the hospital due to subcutaneous tissue induration and skin dis-coloration above the lesion. The skin ultrasound examination showed foci of homo-geneously hyperechogenic subcutaneous tissue thickened up to 6 mm. Furtherexaminations did not reveal any abnormalities besides the slightly increased calci-um concentration (1,69 mmol/l with normal range of 1,2 mmo/l). In order to diag-nose the condition a tissue sample was collected. The histological examinationrevealed panniculitis with infiltration with mononuclear cells, e.g. macrophages aswell as multinucleated giant cells with radial arrangement of needles-shaped cleftsin cytoplasm. After treatment with corticosteroids resolution of all the lesions wasnoted.Key words: subcutaneous fat necrosis, perinatal stress, hypodermatitis.IntroductionSubcutaneous fat necrosis (SFN or SCFN) is anuncommon, transistent, self-limited benign deseaseaffecting adipose tissue of full-term or postamaturenewborn usually with a history of perinatal stress.This condition usually appears within the first 6 weeks of life. Characteristic skin lesions comprisesubcutaneous, mobile painless nodules or plaques.Typically they are located on the buttocks, cheeks,posterior trunk, arms and legs. The skin over thelesions may be violaceus, erythematous or normal inappearance. Prognosis is generally good and in themajority of cases the lesions resolve spontaneouslywithout scarring. Hypercalcemia is the main acutecomplication that is accompanied by SFN and maybe life threating.The pathogenesis of SFN remains unkown. How-ever neonatal hypoxia or hypothermia for variousreasons and local pressure trauma could play somerole in promoting the process.Case reportThree-week old newborn was admitted to theNo1 University Hospital in Bydgoszcz, the Chairand Department of Paediatric Surgery. The child'sgeneral condition at the admition was good. Themain finding in this patient was a skin lesion on theQUIZCORRECT ANSWER TO THE QUIZ. CHECK YOUR DIAGNOSIS241back in the form of subcutaneous tissue indurationwith diameter of 3 × 5 cm (Fig. 1). The lesionappeared in the second week of the newborn's life.The size of the eruption was gradually increasing.When the newborn was being admitted to the hos-pital it was discovered that the skin of the back, rightarm and right buttock was discolourated. The childwas also diagnosed as subcutaneous tissue indura-tion. Further examinations did not reveal any abnor-malities besides the slightly increased serum calciumconcentration (e.g. 1,69 mmol/l with normal rangeof 1,2 mmo/l). The ultrasound scan showed a homo-geneously hyperechogenic subcutaneous tissuethickened up to 6 mm (Fig. 2). The patient was thefirst child of young and healthy parents. The medicalhistory revealed there were pregnancy complicationsresulting from the mother's accidental fall in the38Hbd which caused premature placental ablation.The girl was born in spontaneous delivery in the 40Hbd with body weight of 3480g in poor generalcondition. The newborn Apgar score was 3 points inthe first minute and 6 points in the fifth minute ofpostnatal life. Aditionaly inborn pneumonia andperinatal oxygen deficiency in tissues were diag-nosted. In order to diagnose the condition a tissue samplewas taken and sent to the our Chair and Departmentof Clinical Pathology. We received formalin fixed spec-imen taken from the back that was composed of der-mis and hypodermis. The diameter of the skin samplewas 3 × 5 cm. The surface of the skin didn’t reveal anychanges but white and grey colour of the cut surfacewas noted. After macroscopic examination paraffinblocks were prepared. Hematoksylin-eosin stainingwas made on deparaffinized and rehydratated paraffintissue section (5 μm). The microscopic examinationdemonstrated that there wasn’t any changes in epider-mis, dermis and upper layers of hypodermis (Fig. 3, 4),but patchy areas of fat necrosis and panniculitis inlower part of hypodermis were indicated. A high-pow-Fig. 1. A three-week old newborn with subcutaneousmobile and erythematosus lesions on the back withdiameter of 3 × 5 cmFig. 2. The ultrasound scan demonstratesa homogenously hiperechogenic subcutaneous tissuethicked up to 6 mmFig. 3. Skin biopsy reveals normal structure of epidermis,dermis and upper layers of hypodermis. HE, objectivemagnification 4×Fig. 4. Within lower part of hypodermis areas of necrosiswith inflammatory infiltrate composed mainly bymononuclear cells as well as some multinucleated cells.HE, objective magnification 10×SUBCUTANEOUS FAT NECROSIS OF THE NEWBORN242er view showed that the inflammatory infiltrate con-tained mononuclear cells mainly macrophages andmultinucleated giant cells. The characteristic histolog-ical findings of SFN showed needle-shaped crystals(Fig. 5). Needle-shaped clefts were arranged radiallyin cytoplasm of the macrophages, multinucleatedgiant cells and adipocytes. The foci of calcium andfibrosis weren’t observed.After the diagnosis the child was transfered to theChildren's Hospital in Bydgoszcz and treated withsteroids. A gradual complete resolution of all thelesions was noted.DiscussionSubcutaneous fat necrosis of newborn is a rarecondition in healthy babies born as full-term or pro-longed pregnancy [1]. The real frequency of thiscondition has not been established yet. Predilectionfor gender and race has not been established either[2]. Skin lesions appear in the first few weeks ofa newborn's life, usually between 1st and 6th weekafter the delivery. They are indurations described assubcutaneous tissue in the form of nodules or moreextensive plaques [1]. The lesions are usually painlessduring palpation, mobile and well- defined. The skinover the lesions is either red or red and purple incolour, although it is also possible that the skin overthe lesions remains its natural colour [3]. Most oftenthe lesions appear on the trunk, especially the backand than in decreasing incidence on buttocks, arms,tighs, chin, and cheeks [2]. In most cases spontaneous resolution of the sub-cutaneous nodules leave any lesions. Eruption soft-ening, liquefaction and oozing with subsequent heal-ing process with scar formation or with atrophicallesions have been recorded and described also. Calci-fication of the eruptions can occur with diverse inte-sity and can be revealed in the ultrasonographictechniques [3, 4]. One of the rare complication of subcutaneous fatnecrosis of newborn is hypercalcemia. It occurs with-in 1-4th month after appearing the first lesions. Theclinical symptoms of hypercalcemia expressed in lab-oratory findings as high calcium concentration in theblood serum. They include such phenomenons asirritability, convulsions, failure to thrive or nephro-calcinosis [2, 4, 5]. Hypercalcaemia can become thecause of death and, therefore, even after the lesionsresolution it is necessary to monitor calcium concen-tration in the blood serum in the first six months ofthe child's life [6]. Other rare complications, e.g.thrombocytopenia, hypoglycaemia or hypertriglyc-eridaemia have also been described [3-5]. Calcium concentration increase is believed to becaused by active vitamin D3 (1,25 dihydroxychole-calcyferol), produced by active macrophages in gran-ulation, analogically to sarcoidosis. The active formof vitamin D3 causes increased absorption of calciumin kidneys and the gastrointestinal tract [4, 7, 8].In majority cases the patient is diagnosed basedon the clinical picture. In some cases might be help-ful to perform histopathological study of the skinsample collected from the patient. As an alternative,the sample can be collected in fine-needle biopsy [3].In this presented patient the histopathological exam-ination showed steatonecrosis foci with foci of calci-fication, as well as granulomatous inflammation withmononuclear cells, macrophages and multinucleatedgiant cells. One of the characteristic feature is thepresence of radially arranged, needle-shaped cleftswithin cytoplasm of macrophages or multinucleatedgiant cells and lipocytes [2, 3, 9, 10]. The etiopathogenesis of this condition has notbeen entirely clarified. To cover as much as possiblerisk factors it is necessary to take into considerationa wide range of the perinatal stress conditions suchas: meconium aspiration, placenta praevia, pre -eclampsia, surgeries in hypothermia, Rh factorincompatibility, mother's addiction to cocaine [2, 4,6, 8, 11]. There even was described a case of subcu-taneous fat necrosis of newborn, in whom the moth-er of the newborn had suffered from antiphospho-lipid syndrome and protein C deficiency. Anotherrather interesting description covers a case of a new-born who had been exposed to a low temperatureprocedure according to stimulate the pneumogastricnerve in order to treat supraventricular tachycardia.It is highly probable that oxygen deficiency in tissuesalone and/or hypothermia are the main factors thatinitiate the subcutaneous fat damage and than fol-lowed by its necrosis [2]. Traumatic and physical fac-tors may also be relevant, as frequency of subcuta-neous fat necrosis of newborn babies born inFig. 5. The most characteristic feature of SFN are needle-shaped clefts arranged radially in cytoplasm of themacrophages, multinucleated giant cells and adipocytes.HE. Prim. obj. magnification 40×ANDRZEJ MARSZAŁEK, JOANNA MACIEJEWSKA, MONIKA BOWSZYC-DMOCHOWSKA, ET AL.243SUBCUTANEOUS FAT NECROSIS OF THE NEWBORNspontaneous delivery is much higher than in case ofbabies born by caesarean section. Such influence ofphysical factors seems to be proved by the fact thatsubcutaneous fat necrosis of newborn occurs muchmore often in cases of a complicated or protractedlabour, as well as in an instrumental delivery. Dis-tinctive features visible in the histological examina-tion result from the fatty acids crystallization. New-born's fatty tissue consists mainly of saturated fattyacids (palmitic and stearic acids). Fatty acids aredominant most likely because of the immaturity ofthe newborn's enzyme systems or metabolic disor-ders hindering the reduction in subcutaneous fatTheir melting temperature is relatively high andreaches 64°C. In cases of subcutaneous fat necrosis ofnewborn with hypothermia, saturated fatty acidscrystallize to create radially arranged needles-shapedclefts [2, 4, 8, 12]. In differential diagnosis it is necessary to distin-guish between subcutaneous fat necrosis of newbornand sclerema neonatorum. The later is another veryrare condition with not entirely clear pathogenesis. Inpremature infants and newborns in a poor generalcondition (with congenital heart disease, septic state,respiratory failure), lesions can be diagnosed earlier,in the first week of the newborn's life (most oftenbetween postnatal 2-4 day). In sclerema neonatorumthe subcutaneous tissue induration appears at first onthe shin and thigh and then it spreads in the proximaldirection to reach the whole body, with the exceptionof palms, feet and the urogenital area. The skin overthe induration is pale, waxen or pale-yellow. In thehistological examination sclerema neonatorum, fatnecrosis and/or foci of calcification do not occur.However, it does involve fibrous septa thickening andoedema. The inflammatory infiltration consists oflymphocytes, macrophages and multinucleated giantcells, as it is in case of subcutaneous fat necrosis ofnewborn. In sclerema neonatorum, however, theinflammatory infiltration is not that much intensifiedand it does not include granulomatous inflammation.Furthermore, in SFN there are much more commonneedles-shaped clefts in macrophages and multinu-cleated giant cells [2, 9, 10]. Another condition that must be taken into consid-eration in SFN differential diagnosis is cold panni-culitis. Clinically, a red-and-purple indurationappears within 72 hours from the exposure of thespot to low temperature. The histological examina-tion shows inflammatory infiltrations. Prognosis inboth cold panniculitis and subcutaneous fat necrosisof newborn is promissing. In the differentiation diag-nostics serious cases of dermatitis and panniculitis,such as cellulitis or erysipelas, should also be takeninto consideration [2]. These conditions are accompa-nied by intesive systemic symptoms, such as fever,shiver and bad physical and mental state. The lesionis an erythematosus inflammation, with increasedtemperature and tenderness during palpation. Inerysipelas the inflammatory focus is well-defined,with a smooth, glossy and taut surface. In erysipelasthe inflammatory infiltration affects the dermis, epi-dermis and the outer layer of the subcutaneous tissue.In newborns, it occurs most often around the umbil-ical stump. In the case of cellulitis the lesion is not aswell- defined as in the previous menthioned disease.One can see that it in red and purple lesion and it isusually placed on the cheek. The histological exami-nation shows an abundant inflammatory infiltrationof neutrophiles and the dilation of blood vessels. Incellulitis neutrophiles occur mostly in the inner layerof the dermis and in the subcutaneous tissue [13, 14].As subcutaneous fat necrosis of newborn mani-fests itself as hard and palpable nodules under thedermis, another conditions that should be taken aresuch conditions as angioma and neurofibroma. Theyare examples of easily palpable lesions, too [2]. Cap-illary hemangioma and cavernous hemangioma aresoft, red, lobuliformy nodules and they can appearon the body at the moment of birth (cavernoushemangioma) or in the first few months of the new-born's life (capillary hemangioma). Histologicalexamination is crucial in the diagnosis, as it showsmany capillary canals or larger spaces with endothe-lium. Neurofibromas, especially plexiform neurofi-broma can occur as single or multiple lesions. Theyare spread on a wide range and create not well-defined, soft areas, which in the histological exami-nation will be show as proliferating perineuriumcells, with the extracellular matrix [15-17].Yet another condition is Farber’s disease, a raregenetically determined, autosomaly regressive inher-ited condition. This condition should also be takeninto consideration under disscussion on SFN as itoften affects the dermis. Due to ceramidosis deffi-ciency, ceramides concentrate in macrophages. Clin-ical examination reveals nodules concentratedaround joints (elbows and knees) and in the subcuta-neous tissue, especially on auricle, neck and fingers.Such lesions are accompanied by pain and limitedmobility of the joints. Mental disability is clinicallyclearly recognized. Additionaly hoarseness might befound, as the larynx is also affected. The histologicalexamination shows macrophages with ceramides butwith lack of radially arranged, needles-shaped clefts,lymphocytes and multinucleated giant cells. In olderlesions fibrous connective tissue can also occur [18].ConclusionsSubcutaneous fat necrosis of newborn is a rarecondition diagnosed usually based on the clinical pic-ture. However, in the described case it was necessaryto collect a skin sample in order to make properdiagnosis. The histological examination does notusually leave any doubts. In the differentiation diag-nostics sclerema neonatorum is the first conditiontaken into consideration, with its first lesions, butclinical data should help the proper differential diag-nosis. The differences are also visible in the histolog-ical examination of skin biopsy. Then, one shouldtake into consideration other conditions with symp-toms such as indurated nodules in the subcutaneoustissue. In these cases the histological examination isdecisive. Skin lesions usually regress spontaneouslywithout treatment. In this case lesions regressedafter steroid therapy. Subcutaneous fat necrosis ofnewborn usually runs a mild course. One of rarecomplications described in literature is hypercal-caemia. In the case described the concentration ofcalcium in the blood serum was increased. It wasproposed by some authors that the history of perina-tal stress might initiate skin lesions. Reference1. Wiatrowski T, Marshman G. Subcutaneous FAT necrosis ofthe newborn following hypothermia and complicated by painand hypercalcemia. Australasian Journal of Dermatology2001; 42: 207-210.2. http://emedicine.medscape.com/article/1081910-overview 3. Fenniche S, Daound L. Subcutaneous FAT necrosis: Raport oftwo casus. Dermatol Online J 2004; 10: 12.4. Tran JT, Sheth AP. Complications of subcutaneous FATnecrosis of the newborn: a case report and review of literature.Pediatric Dermatology 2003; 20: 257-261.5. Vijayakumar M, Prahlad N. Subcutaneous Fat Necrosis withHiperkalcemia. Indian Pediatrics 2006; 43: 360-363.6. Burden AD, Krafchik BR. Subcutaneous FAT Necrosis of theNewborn: A Review of 11 Cases. Pediatric Dermatology1999;16: 384-387.7. Bonnemains L, Rouleau S. Severe neonatal hypercalcemiacaused by sybcutaneous FAT necrosis with any apparent cuta-neous lesion. Eur J Pediatrcs 2008; 167: 1459-1461. 8. Kerachristou K, Siahanidou T. Subcutaneous FAT necrosisassociated with severe hypocalcemia. Journal of Perinatology2006; 26: 64-66.9. Aljaser F, Einstein M. A 1-week-old newborn with hypercal-cemia and palpable nodules: subcutaneous FAT necrosis. TheCanadian Journal of Medical Association 2008; 178: 1653-1654.10.  Zeb A, Darmstadt GL. Sclerema neonatorum: a review ofnomenclature, clinical presentation, histological findings, diif-ferential diagnosis and management. J Perinatol 2008; 28:453-460.11.  Mahe E, Girszyn N. Subcutaneous fat necrosis of the new-born: a systematic evaluation of risk factor, clinical manifesta-tions, complications and outcome of 16 children. PediatricDermatology 2007; 156: 709-715.12. Hicks M, Moise L. Subcutaneous fat necrosis of the newbornand hypercalcemia: case report and review of the literature.Pediatric Dermatology 2008;10: 271-276.13. http://emedicine.medscape.com/article/1052445-diagnosis.14. http://emedicine.medscape.com/article/1053686-diagnosis.15. http://pathologyoutlines.com/softtissue3.html.16. http://pathologyoutlines.com/topic//softtissue3neurofbroma-plexiform.html.17. Rosai J. Rosai and Ackerman’s Surgical Pathology 9th edition,Mosby 2004; 2266-69, 2285-2287.18. Yager AM, Armfield U. Bone marrow transplanation forinfant ile ceramidase deficiency (Farber disease). Bone marrowtransplantation 2000; 26: 357-363. Address for correspondenceAndrzej Marszałek, MD, PhDDepartment of Clinical Pathomorphology CM UMKul. Skłodowskiej-Curie Str.985-094 Bydgoszcz phone: +48 52 5854200fax: +48 52 585 40 49e-mail: amars@cm.umk.plANDRZEJ MARSZAŁEK, JOANNA MACIEJEWSKA, MONIKA BOWSZYC-DMOCHOWSKA, ET AL.244THE AUTHORS OF CORRECT DIAGNOSIS IS:Katarzyna Milian-Ciesielska, Department of Pathomorphology, Collegium Medicum, Jagiellonian University, ul. Grzegórzecka 16, 31-531 Kraków

Subcutaneous fat necrosis of the newborn : a case report and review of literature

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Subcutaneous fat necrosis of the newborn : a case report and review of literature

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