Primary Bone Lymphoma: A Rare Case of Anaplastic Large Cell Lymphoma in Calcaneus in a Child.

INTRODUCTION: Primary bone lymphomas are rare, and primary anaplastic large cell lymphomas (ALCLs) of bone in a child are even rarer. A case of primary ALCL of calcaneus in a 7-year-old child is presented. CASE REPORT: Child aged 7 years presented with fungating swelling over his right heel which was associated with fever. The diagnosis was established by immunohistochemistry (CD30, ALK) of the biopsied specimen. Treatment was done by chemotherapy and subsequent radiotherapy. At 12-month follow-up, the child was ambulant with complete resolution of the swelling.
CONCLUSION: Masses arising from the foot and ankle can be a diagnostic challenge, and both infection and neoplasm should be considered in its differentials. Copyright: © Indian Orthopaedic Research Group.

Aggressive fungating lesions which start as swelling over foot in a child can be a very unrelated hematological malignancy instead of any local neoplasm or infection.

Introduction

Lymphomas are a heterogeneous group of neoplasms arising from lymphocytes which can be nodal as well as extranodal. Osseous extranodal lymphoma is a rare entity which comprises around 5% of all primary bone tumors [1]. The femur, tibia, and pelvis are the most common sites of primary bone lymphoma (PBL). A few case reports of PBL in the foot have been described in adults which are histologically diffuse B-cell lymphoma [2, 3, 4, 5]. We present a rare case of anaplastic large cell lymphoma (ALCL) affecting the calcaneus in a 7-year-old child.

Case Report

A 7-year-old male child presented with swelling and pain in the outer aspect of the right heel for past 1 month. Mother of the child correlated the swelling with a history of trivial trauma. The swelling was gradually progressing. A history of incision and drainage of swelling by a local practitioner after 5 days of onset of swelling was noted. There was an associated history of high-grade fever of insidious onset, intermittent in nature with chills and without any diurnal variation. Constitutional symptoms such as significant weight loss, loss of appetite, and malaise were present for the past 2 weeks. He was unable to walk or weight bear due to pain in right lower limb for the past 1 week. The patient was febrile and having tachycardia at presentation. No lymphadenopathy was detected clinically.

A swelling of 5*4*2 cm size which was tender was present over the posterolateral aspect of heel extending anteriorly covering lateral malleolus, posteriorly extending to the area of tendoachilles insertion to the calcaneus, superiorly 5 cm above whole of the lateral malleolus, and inferiorly 2 cm above the heel (Fig. 1). It had an irregular surface, well-defined round margins with loss of skin cover in more than 50% of the surface area with reddish brown color. There was active oozing of blood from the superior and inferior edge of the swelling. Temperature around swelling was raised. Lateral malleolus was not separately palpable from swelling. Tendoachilles could be separately palpable. Ankle motion was restricted and painful with no distal neuro deficits.

Figure 1

(a and b) Showing swelling at presentation and (c) showing swelling fungating with sloughing of skin after 2 weeks.

X-ray showed large soft-tissue shadow over heel with loss of soft-tissue planes and a lytic lesion over the posterior aspect of the calcaneus with destruction of the posterior tuberosity of calcaneus (Fig. 2a). Magnetic resonance imaging showed a lobulated well-defined mass of size 5*3.5*6 cm in the posterolateral aspect of the ankle with hyperintensity in T2 and T1 images (Fig. 2b-e). The mass invaded calcaneus posteriorly with encasement of tendoachilles. Peroneal tendons were free. Diagnosis of soft-tissue sarcoma was made.

Figure 2

(a) X-ray showing soft-tissue mass on posterior aspect of calcaneum with a lytic area. (b-e) Magnetic resonance imaging showing hyperintense lesion in T1 as well as T2-weighted images in posteroinferior aspect of calcaneum.

The initial two core biopsies were non-confirmatory, one of which showed features of acute inflammation with no evidence of malignancy. Aerobic, non-aerobic, or fungal cultures were negative. The swelling increased in size and turned into a fungating mass with sloughs hanging from the surface within 2-week duration after the presentation (Fig. 1). An excisional biopsy of the swelling finally showed features suggestive of non-Hodgkin’s lymphoma. The tumor mass was found to be eroding into the posterior aspect of calcaneum with the involvement of the insertion site of tendoachilles (Fig. 3). The swelling was curetted out till the healthy-looking bone was noticed along with partial excision of the encased tendoachilles. Intraoperatively skin closure could not be achieved. The wound gradually decreased in size with 5 days of continuous vacuum-assisted closure therapy at 125 mmHg (Fig. 4), and it healed with secondary intention with regular dressing within 4 weeks. The range of motion of the ankle and subtalar joint was reduced compared to the unaffected side. Gradual range of motion exercises was started for ankle and foot. In microscopy, the tumor showed sheets of tumor cells intermediate to large cells with moderate amount of amphophilic to eosinophilic cytoplasm and the nuclei appeared to be vesicular with multiple conspicuous nucleoli with some cells showing eccentrically located nuclei and nuclear membrane irregularities (Fig. 5). Immunohistochemistry showed ALK, CD30, CD99, EMA, ki67, and leukocyte common antigen positivity (Figs. 6 and 7).

Figure 3

Intraoperative picture showing mass eroding into calcaneum.

Figure 4

Granulation tissue covering calcaneum after 48 h of vacuum-assisted closure therapy.

Figure 5

(a) At lower power, numerous pale tangible body macrophages are seen, producing a “starry sky” appearance (b) At high power, tumor cells have multiple small nucleoli and high mitotic index.

Figure 6

Immunohistochemistry panel, (a) ALK positive, (b) CD30 positive, (c) ki67 positive, and (d) leukocyte common antigen positive.

Figure 7

Immunohistochemistry panel, (a) EMA positive, (b) CD99 positive, (c) CD3 negative.

Staging of the patient was done by ruling out any synchronous or metachronous disease elsewhere by doing CT scan of chest and abdomen and bilateral bone marrow biopsy. Hence, a diagnosis of PBL with a histological diagnosis of ALCL was made. Treatment was carried out as advised by the oncology team, with 3 cycles of chemotherapy (CHOP – cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by 5 cycles of localized radiotherapy. Supportive treatment in terms of prevention of anemia and infection was given. He did not have any presentation of any diseased lymphadenopathy or organomegaly during the course of treatment. At the last follow-up at 12 months, the wound over the posterior aspect had healed with the patient being ambulatory.

Discussion

Diagnosis of a swelling or fungating growth of the foot in a child can be a diagnostic challenge. Acute as well as chronic osteomyelitis along with benign and malignant lesions can present with such a scenario which can be ruled out by clinical features, laboratory investigations, and confirmed by a tissue diagnosis. The differentials for the malignant and benign conditions are presented (Table 1).

Table 1

Differentials for causes of foot swellings

PBL is defined as (1) a single bone lesion, with or without the involvement of regional lymph nodes and (2) multiple bone lesions without lymph nodal or visceral diseases [6]. The case presented is rare in terms of the age of presentation, the location of the mass as well as the histological diagnosis. The PBLs of foot and ankle that have been reported in the literature were in adults [2, 3, 4, 5]. The histological peculiarity of this case was in terms of ALCL which was ALK positive.

ALCL is the most common T-cell neoplasm in children and adolescents. ALCL primarily involves lymph nodes with extranodal involvement of skin, soft tissue, or lung with primary involvement of bone being rare. ALCL has been divided further by the WHO into – (1) ALK-positive, (2) ALK-negative, and (3) primary cutaneous ALCL. Most of the ALCL presenting in children are ALK-positive. They also mimic as non-lymphomatous lesions. Case reports of being initially diagnosed as neuroblastoma or rhabdomyosarcoma are present [7]. They usually present at an advanced stage of disease with frequent extranodal involvement. Cases of primary bone ALCL have been reported [8]. The diagnosis is primarily based on immunohistochemistry with CD30 positivity. In a review of literature of ALK-positive ALCL with bony involvement, none of the cases reported were involving hand or foot (Table 2) [9-26]. The common sites involved were spine, pelvis, and femur. To date, the most effective treatment has been chemotherapy using CHOP regimen. Surgery is indicated for a destructive lesion in a weight-bearing bone or any pathological fracture. Irradiation therapy alone or in conjunction with chemotherapy has not shown improvement of overall survival in a mono-ostotic disease [11].

Table 2

Summary of cases from 2006 to 2018 reporting ALK-positive ALCL

Conclusion

PBL and more precisely, primary ALCL in bone is rare in younger age group. The common site involved is axial skeleton. A high degree of suspicion with good pathological support is required to make a diagnosis of ALCL at uncommon sites. ALK-positive ALCL has shown to have good remission rates to chemotherapy.

Fungating mass over the heel with lytic expansile lesion over the calcaneum is an enigma in pediatric population. Neoplastic as well as infective conditions both typical and atypical should be considered in the differentials in the workup of such a case. Histopathological examination holds the key in such cases.