ULTRASOUND EVALUATION OF FOREARM ULNAR NERVE SCHWANNOMA

Schwannoma is an a well defined  encapsulated tumor of nerve sheath that grow eccentrically along the nerve axis, within the epineurium .  Schwannoma derive from cells representing the supporting tissue of a nerve, &  they typically appear as ovoid mass arising from the surface of a nerve separated from the unimpaired nerve fascicles . The nerve usually  stretched  & eccentrically courses over the capsule of the mass.  Sonography is usually unreliable in distinguishing between schwannomas and neurofibromas, as  both appears  as discrete homogeneous ovoid hypoechoic masses, with a healthy nerve at the proximal and distal ends of the mass .  A reliable sonographic diagnosis of a nerve tumor can only be made when the lesion found to be in continuity with nerve . The presence of cystic degeneration favours schwannoma rather than neurofibroma . Neurofibroma are surgically inseparable from the host nerve and can undergo malignant transformation ,where as schwannoa being discrete & eccentric ,  thus ,  often allowing the tumor to be surgically excised without loss of neurologic function.

CASE – A 35 y male presented with a small nodular swelling in distal part of  left forearm along ulnar aspest near wrist . The nodule was slightly painful and causes pain in ulnar half of hand on compressing it . No overlying skin changes or pulsations seen . No any pain noted on digital or wrist movements.

AT USG – A well defined encapsulated  oval hypoechoic solid nodular mass of about  16 x 10 x 12 mm size noted in inter mascular plane along ulnar vessels proximal to left wrist [ fig 1 ]. The lesion was  seen along ulnar nerve with neural fascicular continuity present &  established proximal & distal to the mass [ fig 2]. No significant internal vascularity or cystic or calcific foci noted . Adjacent ulnar vessels were  also seen normal . No muscle or bony or wrist  joint pathology seen . In view of encapsulated  focal nodular mass along ulnar nerve, a possible diagnosis of nerve tumor , likely schwannoma was made .  The lesion was proved ulnar nerve schwannoma  at surgery & biopsy [ fig 3 & 4 ].  

                                   Fig 1- LS & TS US scans of left distal forearm proximal to wrist,  showing a well defined hypoechoic  solid nodular mass adjacent to ulnar vessels [ along neurovascular bundle ] 

                                  Fig 2 - LS scan with conjoint image of the mass  , here the mass shows ulnar nerve fascicular continuity at its both proximal & distal ends , suggests the diagnosis of nerve tumor[ schwannoma ]

                                 Fig 3 - Per operative view of the nerve tumor . The tumor was removed without any neural damage .

                                     Fig 4 - Post operative gross specimen of dissected ulnar nerve sheath tumor [ schwannoma ]

PS – The case study in intended for medical professionals & imaging specialists for academic purpose.

  - My special thanks to Dr. Vishal Gupta , orthopaedic surgeon , Bhilwara [ raj., India ] , for operative feed back.


Read More: 1[  http://www.ajronline.org/doi/full/10.2214/ajr.182.1.1820123

                   2]  Peer et al J Ultrasound Med 21:315–322, 2002

NASOLABIAL CYST - An ultrasound evaluation

The nasolabial cyst is a rare non-odontogenic [ extraosseous ] cyst usually develops in the lower region of the nasal ala . Mostly its etiopathogenesis is uncertain .  It is more common in females at about age of forty . The cyst grows slowly and measures between 1.5 and 3 cm in size  It is characterized clinically by a floating structure in the nasolabial sulcus, which usually elevates the upper lip. It is also known as nasoalveolar cyst or Klestadt’s cyst . Its treatment is surgical excision through sublabial incision. Its recurrence is uncommon after complete removal .

CASE - This  is a 43 yrs female patient that presented with a firm swelling in the right alar region of the nose at nasolabial junction , slightly elevating the part of upper lip and nasal ala ; the clinical features suggested a nasolabial cyst.  HRSG scans revealed a well defined subtle thick and regular walled cystic lesion measuring  about 12 x 9 x 11 mm size in the  right ala of the nose [ fig 1-2 ].  No internal echos or septa or solid mural nodule is seen . It is slightly abutting underlying bone .

Fig 1- Slight oblique USG scan of right nasolabial junction showing  a well defined rounded cystic mass consistent with nasolabial cyst. No internal echos or septa or solid mural nodule is seen . Its wall is subtle thick & regular.

 Fig 2- Orthogonal US scans showing the dimensions of  the cyst

PS : The case is intended for academic purpose .

Ref : 1] http://radiopaedia.org/articles/nasolabial-cyst

ULTRASOUND EVALUATION OF MUSCLE HERNIA

ULTRASOUND EVALUATION OF MUSCLE HERNIA

Most muscle hernias occur in the lower leg and affect the tibialis anterior muscle , and are attributed to occupational and sporting activities, trauma , chronic compartment syndrome, and weakness in the overlying fascia due to perforating vessels. It is seen  as a result of muscle protrusion through a defect in the muscle  fascia into the subcutaneous fat and eventually seen as  an overlying bulging soft-tissue mass , making slight contour hump. The adolescents or young adults are affected more. Clinically a swelling is  seen that usually enlarges when the affected muscle is contracted or the patient is in  standing or erect posture , and reduces when the muscle is relaxed .  Mostly muscle  hernias are asymptomatic and requires no treatment . Those with mild symptoms that may be relieved by support stockings. Patients with severe pain or cramps may require surgery.

At USG -  1 ] Focal thinning and slight elevation of the fascia.

                2] Focal fascial defect with protrusion or bulge  of muscle fibres through the defect  when the muscle                     is contracted , and making a contour hump. [ fig 1,2] 

               3] Prominent arterial pulsation on color or power Doppler - support the theory that muscle herniation                        occurs at sites of weakness in which vessels penetrate the fascia [ fig 3] 

                                          Fig 1 - A 20 yrs young boy presented with a small swelling at mid part of right anterolateral leg , which becomes conspicuous & painful on exercise or on continuous walking .  Long US scan shows focal bulge in tibialis anterior muscle [ arrows] on muscle contraction or on standing 

                                           

                                          Fig 2 - Both LS & TS ultrasound scans of the same case  , shows a small focal defect in the Fascia of tibialis  anterior muscle [ arrow in TS scan ]  with focal muscle fibres bulge or contour hump [ arrow in LS scan ]

                              

                                            Fig 3 - TS & LS ultrasound with color doppler scans shows a prominent vessel , likely perforating artery , at the site of fascial defect & muscle bulge or hernia  

Most muscle hernias do not require any  treatment [  or requires just reassurance] , but some painful cases may needs surgery. Importantly ultrasound is very helpful in apprehensive patients to exclude muscle tears and tumors . 

PS – This presentation is intended for academic purpose esp. for medical professionals & radiologists

Ref - American Journal of Roentgenology. 2003;180: 395-399

      [Read More: http://www.ajronline.org/doi/full/10.2214/ajr.180.2.1800395]

SONOGRAPHIC EVALUATION OF FRACTURE PENIS

ABSTRACT

This case report highlights various aspects of penile fracture, which is a rare urological emergency .  The incidence of penile fracture is slightly increasing these days, may be due to performance enhancing medicines.   It being a medical emergency patient must seek immediate medical support.  A swift diagnosis and management is essential to avoid undesirable after effects as discussed.  This presentation delineates on how sonography helps to make a complete diagnosis of this condition. 

Key words : Penile fracture , sonography , penile trauma, tunica albuginea

INTRODUCTION

Penile fracture is due to rupture of the tunica albuginea sheath covering the erectile corpora cavernosa.  It may involve one or both corpora cavernosa.  The condition is usually under reported due to ethical and phychological reasons observed by the patients .  The diagnosis of fracture penis is usually clinical .  The sonography is asked when the observations are  atypical , and to  confirm the diagnosis , and to evaluate site, size, orientation  and extend of tunical injury along with penile soft tissue status and hematoma.

CASE REPORT

A 36 years old man presented with development of  sudden painful swelling and deformity of the penis following sexual intercourse.  After having strong clinical suspicion of penile fracture, the urologist referred the case for sonographic evaluation .  Sonography of penis was done with  high resolution linear probe  in longitudinal , transverse, oblique and horizontal planes with the region of interest in detail.  USG showed diffuse skin and soft tissue thickening of penis with a small defect in the continuity of tunica albuginea [an echogenic line encircling hypoechoic cavernosa] of Left lateral corpora cavernosa of penile mid shaft [fig 1-3 ].  The defect was about 15 mm in size & transversely oriented  with a large inhomogenic hematoma noted overlying it.  The hematoma  was seen as inhomogenic echopoor & avascular mass adjacent to defect [ fig 1-3] .  Rest of the corpora and spongiosa appeared normal.  Both cavernosal arteries showed normal to little low resistance blood flow pattern [fig 4].   No evidence of corpora spongiosa or urethral injury was seen .  So, based on these ultrasound findings [ that is - cavernosal tunical sheath tear with associated hematoma ] a diagnosis of penile fracture was made  and a detailed report was furnished .  The case was then urgently operated by the urologist [ tunical repair and hematoma drainage ] and the findings were confirmed[fig 5-8 ].  Post operative recovery was uneventful , & the patient behaved normally for erectile function  in subsequent follow-up visits.

Fig 1 – Transverse US  penile scan shows defect in tunical sheath of left corpora cavernosa on lateral aspect [ arrow] with adjacent hematoma

Fig 2- Horizontally oriented longitudinal penile scan showing  tunical sheath defect [ arrow] & overlying penile shaft hematoma.

Fig 3- Both TS & LS color Doppler penile scans showing sheath defect , avascular hematoma  & average vascularity in rest of penile  shaft.

Fig 4 – Spectral Doppler display left cavernosal  artery

Fig 5 – Per op. photograph showing subcut. Penile shaft hematoma

Fig 6 – Per op. photograph depicting sheath defect

Fig 7 – Photograph after tunical sheath repair

Fig 8 – Photograph after complete  penile surgery

[ Operative photographs  courtesy – Dr.  Manish Bhansali ,M.S. , D.N.B.{Urology}, Bhilwara]

 

DISCUSSION

Penile shaft consist of two elongated columns of erectile tissue called corpora cavernosa placed dorsolaterally , and a corpus spongiosum ventrally  containing erectile tissue and urethra.  Each column is enclosed in tunica albuginea sheath which is extension of Buck’s fascia over these cylindrical structures [ 1, 2] .   During erection these corporas enlarges due to blood pooling in vascular sinusoids and the tunica albuginea is thinned .  Any extrinsic bending  force to erected penis causes rupture of tunica due to rapid rise of inside pressure in corporas.  Activities like masturbation , self manipulation, sexual intercourse , and rolling over bed, can cause penile trauma and result in fractures.  Vaginal intercourse being the most common cause [ 3 ] .  Increased use of drugs which enhance the duration of erection [ 4 ], pre-existing penile disease or periurethral infections [ 5 ] increase the chance of penile fractures.  The affected person usually complain [ 1 -2 , 5 ] hearing of , or feeling , a sudden crack  or snap in the penis with  sudden loss of erection  and resultant swollen, deviated, painful penis .  In most of the cases usually one side of distal two third of penile shaft is fractured with less than half of cavernosal circumference affected.  Associated hematoma may be intra- cavernosal , intra and or extra cavernosal or may extend to scrotum, suprabubic area, perineum, and in some cases , even upto thighs .  Associated urethral injury may present as hematuria and dysuria.

The diagnosis of penile fracture is usually clinical, however not  possible make or may be inconclusive sometimes , needs further imaging .  The modalities available are cavernosography, sonography [ USG ] and MRI to confirm and identify penile fractures.   MRI being multiplanar and  with good soft tissue resolution scores over other modalities , however , for practical purposes, sonography preferred over MRI as it is easily available , cost effective , portable radiation free , less time consuming and allows dynamic evaluation of the region of interest [ 6 ].  High resolution sonography clearly depicts penile soft tissue anatomy , outline of corporas including status of tunica albuginea sheath and associated hematoma . Loss of continuity or defect in tunica albuginea with associated hematoma signifies fracture of penile shaft [ as seen in this case] . 

These patients requires early surgical treatment in form of  hematoma removal and tunical repair , which has been stated better than conservative measures [ 3, 5 ] , as this reduces the chance of scarring , angulation deformity and painful erection syndrome consequences.  

This patient was immediately subjected to surgery, which was uneventful, & showed normal postoperative recovery. The patient gave history of  satisfactory penile erection in his follow up visits .

So, it is worth to know about this urogenital emergency by the Doctors , so as to make a swift diagnosis of “ fracture penis “ and to refer such a case for appropriate mamagement to avoid devastating physical, functional and psychological consequences.

CONCLUSION  

A case of penile fracture needs to be diagnosed and treated promptly to avoid complications .  Ultrasound is considered to be an imaging modality  of choice in emergency as it is noninvasive, cost effective , radiation free , easily and widely available and can be repeated even at bed side .   All Doctors must be aware  of this entity in all aspects including clinical perspective , knowing about imaging findings and realising urgent need for treatment to avoid complications.

REFERENCES

1. Bannister LH, Dyson M. Reproductive system. In: Williams PL, editor. Gray's anatomy. 38th ed. New York, NY: Churchill Livingstone; 1995. pp. 1847–1880.

2. Rosse C, Gaddum-Rosse P. Pelvis and perineum. In: Rosse C, Gaddum-Rosse P, editors. Hollinhead’s textbook of anatomy. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997. pp. 639–700.

3. Ruckle HC, Hadley HR, Lui PD. Fracture of penis: diagnosis and management. Urology.1992;40(1):33–35. [PubMed]

4. Blake SM, Bowley DMG, Dickinson A. Fractured penis: Another complication of SILDENAFIL.Grand Rounds. 2002;2:11–12.

5. Brotzman GL. Penile fracture. J Am Board Fam Pract. 1991;4(5):351–353. [PubMed]

6. Nomura JT, Sierzenski PR. Ultrasound diagnosis of penile fracture. J Emerg Med. 2010;38(3):362–365. [PubMed]

7. S. G. Kachewar et al , Ultrasound Evaluation Of Penile Fracture , Biomed Imaging & Interventional Journal  2011 oct-dec ; 7[4]: e27.