Keywords histiocytic sarcoma/pathology - histiocytic sarcoma/diagnostic imaging - histiocytic
sarcoma/surgery
Introduction
Histiocytic sarcoma (HS) is a rare, aggressive neoplasm of high grade and hematopoietic
origin.[1 ]
[2 ] With unknown etiology and rapid clinical evolution, HS may present as a localized
extranodal disease or as a disseminated disease,[1 ]
[3 ] associated with nonspecific systemic symptoms (fever, weight loss, anorexia, asthenia).
Although several HS cases have been described, the primary involvement of the bone
marrow is exceedingly rare,[4 ] as well as its incidence in children.[2 ] There are several types of treatment, including surgery, radiotherapy, chemotherapy,
and their combinations, with a guarded prognosis.[4 ]
Case Report
We report a case of primary bone involvement by HS with a single lesion at the right
scapula of a 15-year-old male patient. The patient initially presented with pain and
swelling of the region with an approximate evolution of 60 days and pain-induced impairment
of the range of motion. About 10 days after the onset of the symptoms, the patient
started to present intermittent, nocturnal fever, of ∼ 38° C (100.4 F), which remitted
with the usual antipyretics. The initial radiography showed a permeative lesion with
lytic aspect at the body of the right scapula up to the medial border, with no cortical
involvement or periosteal reaction. Imaging techniques were used to evaluate the extension
of the disease. A computed tomography (CT) scan ([Fig. 1 ]) also evidenced a permeative lesion in the location previously noted at the plain
radiography, with no associated pathological fracture, infiltrating the adjacent soft
tissues. A supplementary imaging study of bone scintigraphy confirmed the presence
of a hyperuptake zone at the right scapula. A needle biopsy determined the diagnosis
of bony histiocytic sarcoma with the analysis of anatomopathological and immunophenotypic
markers.
Fig. 1 Computed tomography 3D reconstruction showing the lesion.
A multidisciplinary team evaluation determined the preoperative institution of neoadjuvant
chemotherapy according to the protocol for Ewing sarcoma. The respective chemotherapy
cycles were followed by the surgical treatment according to the modified Tikhoff-Linberg
type II technique, with wide tumoral resection and partial amputation of the right
scapula ([Figs. 2 ] and [3 ]). The patient used a simple Velpeau immobilizer for 8 weeks after the surgery, followed
by a new chemotherapy cycle based on the Brazilian protocol for Ewing sarcoma. At
the oncological and subsequent physical therapy follow-up, the patient presented an
important improvement of the instrumented limb range of motion and function ([Fig. 4 ]), and no pain.
Fig. 2 Surgical planning of the incision.
Fig. 3 Resected surgical specimen.
Fig. 4 Residual range of motion after surgical treatment and physical therapy.
Twenty-four months after the procedure, the patient was disease-free, totally reintegrated
to his social, educational, and sporting activities, asymptomatic, and medically and
esthetically satisfied with the treatment.
Discussion
Histiocytic sarcoma represents < 1% of the hematopoietic tumors, and it is characterized
by the proliferation of malignant cells with morphological and immunohistochemical
patterns based in mature tissue hystiocytes.[3 ] With no well-established etiological factors, HS has an aggressive evolutive character
and affects slightly more men than women, with an average age of 46 years old.[3 ] The presentation depends on the affected location.[2 ] The extranodal disease might be confined to the skin, to the lymph nodes, and to
the intestinal tract.[3 ] The disseminated disease is associated with systemic symptoms, such as hyperthermia,
weight loss, anorexia, and asthenia.
Several HS cases were erroneously diagnosed as lymphomas, leukemias or carcinomas.[2 ] There are reports of some HS cases with subsequent or coexisting occurrence of lymphoma/B
or T cell leukemia.[3 ] The definitive diagnosis of the disease is established by an anatomopathological
study of the affected organ: bone marrow biopsy with immunophenotypic analysis.[2 ] The disease is characterized by the proliferation of histiocytes with positive expression
of macrophage-associated antigen CD68, CD21, and CD35.[1 ]
[3 ] Histiocytic sarcoma must be morphologically differentiated from inflammatory pseudotumor,
dendritic cell sarcomas, malignant Langerhans cells histiocytosis, anaplastic large
cell lymphoma, melanoma, and other sarcomas.[1 ]
[3 ]
[4 ]
Histiocytic sarcoma is managed according to its stage and site by different approaches,
including surgery, radiotherapy, chemotherapy, and their combinations. The limb-sparing
interscapulothoracic resection (Tikhoff-Linberg surgery) is a surgical option for
bony and soft parts tumors of the proximal humerus and of the shoulder girdle.[5 ] In its classical form, this procedure comprises the resection of the humeral proximal
third and the extra-articular removal of the shoulder joint, of the distal third of
the clavicle, and of the whole scapula and their adjacent soft parts.[5 ]
[6 ] The selected patients must not present tumor in the thoracic wall and in the neurovascular
bundle. The area may be reconstructed with a nonconventional endoprosthesis or with
a homologous bone from a bank; moreover, the area may not be reconstructed with foreign
materials.[5 ] Resection levels are variable and depend on the extension of the tumor ([Fig. 5 ]). Hand and forearm postsurgical function is partially preserved, with elbow flexion
and shoulder stability requiring or not an orthesis, and through careful myotomies,
myorraphies, and residual myoplasties.[5 ]
[6 ] The main postoperative problem is neurapraxia due to nerve traction during dissection,
which normally improves over the first weeks after the procedure.[6 ] However, Tikhoff-Linberg type II surgery, or medial partial scapulectomy, does not
cause this traction, since most of the shoulder girdle is preserved.
Fig. 5 Tikhoff-Linberg surgery and its modifications.[6 ]
The bad prognosis of HS, especially in the disseminated presentation, results from
the difficult systematization of a standard therapeutic protocol with good response.[1 ]
[4 ] In such cases, most patients die from the progressive disease in approximately 2
years.[2 ]
[3 ] The localized disease has a favorable prognosis,[4 ] often associating adjuvant methods (chemotherapy or radiotherapy) with oncological
surgical resection.
Considering the rare nature of the disease and its epidemiological peculiarity, we
emphasize the need to refer this kind of patient to a reference center in orthopedic
oncology hoping to obtain outcomes as satisfactory as those presented here. Tikhoff-Linberg
type II surgery, or medial partial scapulectomy, is a surgical procedure that is an
option to interscapulothoracic amputation for large tumors in the scapulohumeral region
with no invasion of the axillar neurovascular bundle.[5 ]
[6 ]
