Malignant perivascular epithelioid cell tumor in children: description of a case and review of the literature.
Perivascular epithelioid cell tumors (PEComas) include different morphological entities originating from perivascular epithelioid cells. Their clinical behavior is not predictable, and there are no strict histologic criteria for malignancy, although larger tumors with infiltrative growth, hypercellularity, cellular atypia, atypical mitoses, and necrosis generally have a malignant course. Pediatric PEComas are rare, with less than 40 cases reported, mostly in children older than 5 years. We describe a case of malignant PEComa of the ligamentum teres in a 2-year-old girl, characterized by the occurrence of local relapse after primary treatment with chemotherapy and surgery and poor response to imatinib mesilate and temsirolimus used after further analyses confirmed p70S6K expression involved in the mTOR pathway. The girl was eventually treated with a debulking surgical procedure and is now alive with disease 6 years after diagnosis. Literature data of children affected by PEComas were also analyzed, trying to identify pathologic characteristics that could predict their course and therapeutic options. Histologically, they may be differentiated in 3 prognostic categories: (1) benign, lacking unfavorable morphological markers; (2) with uncertain malignant potential, carrying 1 unfavorable marker; and (3) malignant, with at least 2 unfavorable markers. In the literature, 9% of cases occurred as a second malignancy probably because of genomic instability related to treatment. Their different biology and the potential value of targeted therapies remain to be explored. The indolent evolution in our patient was similar to that reported in some other cases in the literature. In terms of treatment, the present case suggests a minor response to temsirolimus compared with the adult population.
Pathology Department, University of Padua, Padua, Italy.
Rita
R
Alaggio
Giovanni
G
Cecchetto
Guido
G
Martignoni
Gianni
G
Bisogno
Liang
L
Cheng
Domenico
D
Sperlì
Emauele S G
ES
d'Amore
Patrizia
P
Dall'Igna
D000008:Abdominal Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001549:Benzamides; D001706:Biopsy; D002675:Child, Preschool; D003131:Combined Modality Therapy; D003951:Diagnostic Errors; D005047:Etoposide / Q000008:administration & dosage; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D007415:Intestinal Obstruction / Q000209:etiology; D008022:Ligaments / Q000473:pathology* / Q000601:surgery; D008113:Liver Neoplasms / Q000188:drug therapy / Q000556:secondary; D009364:Neoplasm Recurrence, Local; D010534:Peritoneal Neoplasms / Q000556:secondary / Q000601:surgery; D054973:Perivascular Epithelioid Cell Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D010879:Piperazines / Q000627:therapeutic use; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use; D011859:Radiography; D018227:Sarcoma, Clear Cell / Q000175:diagnosis; D020123:Sirolimus / Q000008:administration & dosage; D049951:X Chromosome Inactivation
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D005047:Etoposide; D000068877:Imatinib Mesylate; D020123:Sirolimus