Blastomycosis presenting as multiple splenic masses

B LAS TO MY CES DER MA TI TI DIS IS A DI MOR PHIC FUN GUS THAT causes acute or chronic pneu mo nia from in ha la tion of spores from the en vi ron ment (1). He ma toge nous dis semi na tion can fol low, usu ally in volv ing the skin, bone, uro geni tal tract and cen tral nerv ous sys tem, in that or der of fre quency (2). Splenic ab scess as the pre sent ing fea ture due to B der ma ti ti dis is very rare. We re port a case of a pa tient who pre sented with an en larged spleen and ret ro peri to neal ade no pa thy who, on clini cal and ra dio logi cal grounds, was thought to have a meta static dis ease or lym phoma. A com puted to mo gra phy (CT) guided nee dle as pi ra tion bi opsy of the spleen es tab lished the di ag no sis of blas to my co sis. To our knowl edge, this is the first case of splenic blas to my co sis di ag nosed by such a tech nique. As so ci ated ret ro peri to neal ade no pa thy also has not been pre vi ously re ported. CASE PRES EN TA TION A 54yearold fe male resi dent of north west ern On tario pre sented to her fam ily phy si cian in Sep tem ber 1993 with a fourmonth his tory of 20 kg weight loss, night sweats and fa tigue. She de nied cough or hemo ptysis. There were no gas tro in tes ti nal symp toms. She had a 30pack per year smok ing his tory. Past his tory was non con tribu tory. Physi cal ex ami na tion at the time was un re mark able apart from a pal pa ble liver edge. She was afeb rile. Blood work re vealed a he mo glo bin of 101 g/L, white blood cell count of 10.6x109/L, mean cor pus cu lar vol ume 79.9 fL; elec tro lytes and liver func tion tests were nor mal. Chest ra dio graph showed an area of con soli da tion in the right up per lobe with vol ume loss and cavi ta tion. She was re ferred for bron cho scopy. Cul tures from bron cho scopy speci mens were nega tive for my co bac te ria and fun gus. No tu mour cells were found. CASE RE PORT

A Man toux skin test re vealed greater than 15 mm indura tion.She was started em piri cally on isonia zid, pyra zin amide and rifampicin in Oc to ber 1993.She symp to mati cally im proved over two weeks in terms of en ergy level, but then de te rio rated with pro found weak ness.
A CT scan of the ab do men in No vem ber 1993 (Fig ure 1) showed mul ti ple low at tenua tion splenic masses and mild retro peri to neal ade no pa thy.She was re ferred to on col ogy for inves ti ga tion of pos si ble lym phoma or meta static dis ease to the spleen.There was evi dence of an en larged and tender spleen on physi cal ex ami na tion in De cem ber 1993.No other ade nopa thy was evi dent.Fur ther in ves ti ga tion, in clud ing a bone mar row ex ami na tion, was nor mal.A CT scan in Janu ary 1994, com pared with that in No vem ber 1993, re vealed marked decrease in size of the le sions.Ret ro peri to neal ade no pa thy was also evi dent.
CT guided splenic nee dle as pi ra tion bi opsy was per formed.Nu mer ous bud ding yeast or gan isms con sis tent with B der mati ti dis were iden ti fied in the Pa pani co laou, Giemsa and hematoxylin-eosin stained ma te rial.Mor pho logi cal de tail was es pe cially clear in the Pa pani co laou stained smears.Or gan isms were iden ti fied in tra cel lu larly within gi ant macrophages and ex tra cellularly within a pre domi nantly sup pu ra tive back ground.Both the char ac ter is tic sin gle broad-based budding of B der ma ti ti dis and thick re frac tile wall sur round ing proto plasm and nu clear con tents (Fig ure 2) were eas ily iden tified.No hy phae were seen.There was no evi dence of ma lig nancy in the as pi ra tion bi opsy ma te rial.Be cause the sus pi cion of ma lig nancy, such as lym phoma, was high, the very lim ited amount of as pi rated ma te rial avail able was sent for cy to pa thol ogy and im mu no his to chem is try.No fur ther mate rial was avail able for cul ture af ter it was re al ized the cy tology sug gested bud ding or gan isms.
The pa tient was started on am pho tericin B 0.5 mg/ kg/day in early Janu ary 1994, a day af ter the nee dle as pi ra tion biopsy was per formed.Re sponse to an ti fun gal ther apy was rapid.Within a few days, the night sweats and fa tigue ame liorated.She re gained the weight she had lost within three months.An ul tra sound ex ami na tion of the spleen in May 1994 was ab so lutely nor mal.She re mains clini cally free from disease.

DIS CUS SION
Blas to my co sis is en demic in the Mis sis sippi, Ohio and St Law rence River val leys and in north west ern On tario, ex tending into Mani toba (3).
The lungs are the por tal of en try for B der ma ti ti dis via in hala tion of co nidia from the soil in en demic ar eas.Pa tients may pres ent with acute pneu mo nia, but the usual pres en ta tion is that of chronic pneu mo nia with fa tigue, weight loss, pro ductive cough and pos si ble he mop tysis.Di ag no sis is es tab lished by cul ture or histopatho logi cal evalua tion of spu tum or bron chial wash ings ob tained by bron cho scopy (1).Bi opsy of an involved or gan, such as skin, may es tab lish the di ag no sis.
The clini cal and patho logi cal di ag no sis of an overt splenic ab scess due to blas to my co sis is very rare.We are aware of only two cases pre vi ously re ported in the English-language lit era ture (4,5).Both were di ag nosed by lapa rotomy.Sub clinical splenic in volve ment has been docu mented in autopsy series of deaths due to blas to my co sis.In one se ries of

Fig ure 2) Char ac ter is tic broad-based bud ding of Blas to my ces derma ti ti dis (thick ar row) and thick re frac tile cell wall (thin ar row) sur round ing pro to plasm and nu clear con tents (Pa pani co laou stain x740)
Fig ure 1) Com puted to mo gra phy scan of ab do men (No vem ber 1993) show ing mul ti ple low at tenua tion splenic masses blas to my co sis cases from the Vet er ans' Ad min istra tion Hospi tals in the United States in the 1940s and '50s (over a 12year pe riod), splenic in volve ment was found in eight of 198 cases, all dis cov ered post mor tem (6).
Many fac tors made our case an es pe cially dif fi cult di agnos tic chal lenge.No ac tive pul mo nary dis ease was iden ti fied and res pi ra tory cul tures were nega tive for my co bac te ria and fungi.The pri mary site may have re solved spon ta ne ously, or the di ag nos tic tests may have been falsely nega tive.
The ini tial fa vour able clini cal re sponse to tri ple therapy for tu ber cu lo sis and the fact that the splenic le sions par tially responded ra dio logi cally were in ter est ing ob ser va tions.To our knowl edge, there is no pub lished in for ma tion on the sen si tivity of B der ma ti ti dis to an ti tu ber cu lo sis agents.
The pres ence of con sti tu tional symp toms (weight loss, night sweats) and CT evi dence of mul ti ple hypo attenuating le sions with ret ro peri to neal lym pha de no pa thy put lym phoma high on the dif fer en tial di ag no sis.Other patho logi cal processes that may ex hibit simi lar fea tures as visu al ized by CT include meta static in volve ment of spleen, tu ber cu lo sis and sar coi do sis.Simi lar splenic le sions with out as so ci ated lympha de no pa thy may be caused by can didia sis, staphy lo coccus or strep to coc cus in fec tions in as so cia tion with en do car di tis and by aero bic Gram-negative rods, in clud ing sal mo nella.