Case presentation
A 27 year old man consulted for 2 month history of lower urinary tract
symptoms. On physical exam, he had an enlarged smooth nontender
prostate with no nodularities and no blood on examining finger. Traube’s
space was obliterated.
Initial workup showed Hb 8.9 g/dL Hct 26.4 % WBC 7.1 x10^9/L (N54%
L15% E3% M3% St17% Mye2% Metamyelocytes 6%) Platelets 102
x10^9/L. PT 11.8 sec/ INR 0.98/ PTT 24.5 sec. Crea 1.61 mg/dL
(CKD-EPI EGFR 60) BUN 26 mg/dL HCO3 27 meq/L Na 139 mmol/L K 3.4 mmol/L
Cl 101 mmol/L iCa 1.16 mg/dL Mg 1.7 mg/dL, TC 170 mg/dL TAG 127 mg/dL
HDL 51 mg/dL LDL 110 mg/dL ALT 66 IU AST 62 IU TB 0.56 mg/dL CB 0.17
mg/dL UB 0.39 mg/dL ALP 107 IU/L Albumin 4.47 g/dL. Urinalysis light
yellow, clear urine, negative for glucose bile ketones protein nitrites
blood and lymphocytes, SG 1.004, pH 7.0, RBC 0/HPF WBC 0/HPF Epithelial
cells 0/HPF Casts 0/HPF Bacteria 0/HPF. PSA 0.23 ng/mL was normal for
age.
As show in Figure 1, Multiparametric Prostate MRI with contrast showed
markedly enlarged prostate gland with intravesical extension measuring
6.6 x 7.1 x 8.7 cm with a volume of 212 ml with a PIRADS 5 score.
FDG PET-CT showed FDG-avid mass in prostate gland, measuring 8.5 x 7.0 x
6.5 cm SUV 9.6, prominent to enlarged bilateral iliac chain lymph nodes,
enlarged spleen and multiple osseous lytic and blastic lesions in L1 and
L4 vertebral bodies, sacrum and bilateral pelvic bones.
Patient underwent Koelis US-MRI Fusion Transperineal prostate biopsy,
bilateral ureteral stenting, with indwelling foley catheter.
Histopathology showed round cell malignancy, immunohistochemistry
positive for Desmin and myogenin.
As shown in Figure 2, bone marrow showed a markedly hypercellular bone
marrow for age (>95%), with extensive infiltration of
atypical cells and tumor giant cells. Immunohistochemistry was positive
for CD56, Desmin and Myogenin. Genetic tests were positive for PAX3(exon
7):FOXO1(exon 2) fusion gene.
Dynamic Liver CT showed splenomegaly, slightly dilated portal and
splenic veins with gastrosplenic collateral vessels and normal-sized
liver. Liver elastrography was F0.
Diagnosis was Alveolar Rhabdomyosarcoma of the prostate Stage IVB
(cT4N1M1B-bone), with noncirrhotic portal hypertension, postobstructive
uropathy s/p Ureteral stenting bilateral. Patient underwent 3 cycles of
Vincristine (1.5 mg/m2), Dactinomycin (40 mcg/kg) and
Cyclophosphamide (1200 mg/m2) MESNA. He was given
Denosumab every 28 days and Caltrate advanced 2 tabs TID for bone
protection and Carvedilol 6.25 mg daily for portal hypertension.
On serial follow-up, liver enzymes peaked at ALT 375 IU/L, AST 126 IU/L.
Patient was given Legalon 140 mg TID, Transmetil 500 mg OD, Godex DS 300
mg capsule TID, Essentiale forte TID with decrease in liver enzymes.
Creatinine trends remained stable ranging from 0.7 to 0.8 mg/dL.
After 3 cycles, repeat FDG PET-CT showed significant regression in size
and extent of hypermetabolism in the prostatic mass, with interval
increase in hypermetabolic activity in its left prostatic lobe
attributed to residual active malignancy. There was interval
non-demonstration of the hypermetabolic iliac chain lymph nodes, stable
mixed lytic-blastic lesions in the thoraco-lumbar vertebral bodies and
sacrum.