Locally advanced groin neurofibrosarcoma misdiagnosed twice as inguinal hernia: a case report

¹Department of Surgery and Subspecialties, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon, ²Urology Service, Douala Laquintinie Hospital, Douala, Cameroon, ³Urology Service, Yaoundé Central Hospital, Yaoundé, Cameroon

^&Corresponding author
Axel Stephane Nwaha Makon, Department of Surgery and Subspecialties, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon

Introduction    

Neurofibrosarcoma is a peripheral nerve sheet malignant tumour affecting the peripheral nerves. The real incidence and prevalence of these rare tumours is unknown worldwide with current studies estimating it to account for about 3-5% of all soft tissue sarcomas [1,2]. This tumour is very aggressive with a high metastatic and recurrence potential [3]. This tumour originates from the peripheral nerves and occurs mainly in the limbs, head and neck, and spine. Neurofibrosarcoma has a variety of histologic subtypes. Due to the diversity of histologic types, these tumours have a high histologic similarity to other benign and malignant soft tissue tumours. Due to the lack of specific diagnostic criteria, pathologic diagnosis is extremely difficult, since these tumours should be differentiated from other sarcomas according to the site of tumour occurrence and morphologic characteristics, which can be determined using immunohistochemical staining [2]. The incidence of neurofibrosarcoma peaks in individuals between 20 and 50 years of age, with a median age of 44 years [4]. The aetiology of these tumours remains unclear. However, studies have shown that there might be related to neurofibromatosis. The clinical manifestations are primarily enlarged masses, accompanied by pain, compression symptoms, and motor and sensory dysfunction [5]. Following an extensive literature search, very few cases of neurofibrosarcoma have been reported from Africa and no case from Cameroon.

Patient and observation     

Patient and observation: the authors report a case of a 26-year-old male who presented with recurrent right inguinal mass following surgical repair of a right inguinal hernia. He does not report any family history of cancers or genetically predisposed illness. He was diagnosed with a malignant neurofibrosarcoma, and he died 3 months later following tumour resection. This case has been reported in accordance with the CARE guidelines [6].

Case presentation: mr X is a 26-year-old male transferred by his primary care physician (PCP) in March 2021 from a district hospital to our tertiary hospital at Douala Laquinitinie Hospital (DLH) for evaluation and management of a right recurrent ulcerating groin mass. The patient reports that the swollen dates back about 10 months prior to presentation with an inguinal swollen diagnosed initially as right inguinal hernia for which a hernia repair was done by his primary care physician. One month following the inguinal hernia repair, he presented with a larger recurrence of the inguinal mass, prompting a second surgical exploration by the same health care provider. His PCP reports that during the second exploration there was a large necrotic tumour which a biopsy was taken for histopathology and the results came out suggestive of chronic inflammation. Following the 2^nd surgical exploration, the mass increased rapidly in size, extending from the groin to the anterolateral abdominal wall and the left hemi-scrotum. The mass was ulcerative, constantly secreting yellowish offensive fluids. This prompted transferred to our tertiary centre at DLH.

Clinical findings: on arrival and upon physical examination, the patient was cachectic and ill looking, with satisfactory vital signs. There was a giant ulcerative and fungating mass in the right groin extending to the right hemi-scrotum which measures about 30x20x10 cm as shown in the Figure 1.

Diagnostic assessment: the differential diagnosis at entry included testicular tumour and Fournier´s gangrene. The following investigations were requested MRI of the mass and the pelvis, complete blood count (CBC), clotting profile, blood group and Rhesus factor, urea and serum creatinine, lactate dehydrogenese (LDH), alpha fetoprotein (AFP). Magnetic resonance imaging (MRI), AFP and LDH were not done due to financial constraints. The results of biological investigations were as follows: haemglobin of 5g/dl, white cell count of 33000 cells/mm³. Clotting profile and renal functions were normal.

Therapeutic intervention: the immediate management consisted of blood transfusion, fluid and electrolytes correction and antibiotics. A pre-anestheic consultation was done in preparation for excision of the tumour. Surgery was done and consisted of excision of the mass as shown in Figure 2. Histopathology results after surgery were confirmatory of poorly differentiated locally advanced neurofibrosarcma with the margin of resections R2 as shown in Figure 3. Multidisciplinary team (MDT) review was done during the hospital oncology MDT, and he was declared not to be eligible for chemotherapy.

Follow-up and outcome: the postoperative treatment consisted of iterative blood transfusions, multimodal analgesics, antibiotics and local wound care. A month after surgery, the tumour has grown more than it was at initial presentation, as shown in Figure 4. He died three months following surgery.

Discussion     

There is paucity of literature in the epidemiology as well as the presentation and management of malignant neurofibrosarcoma. Here we report a young man with advanced metastatic neurofibrosarcoma of the groin, managed initially as inguinal hernia. The tumour was diagnosed following its second recurrence, presumed to be the second repair of inguinal hernia. Hernia is a common surgical disease, and cases of metastatic carcinoma in inguinal hernias have occasionally been reported [7,8]. Neurofribrosarcoma may occur in three different contexts; associated with neurofibromatosis in about 50% of cases, sporadic in about 40% of cases, as a consequence of previous radiation in about 10% of cases [9]. The index case was not diagnosed of neurofibromatosis, didn´t have features of this disease at presentation and had never been exposed to radiation, and as such the tumour was most likely to be sporadic. Neurofibrosarcoma lacks specific clinical and imaging characteristics, making the diagnosis difficult [3]. These tumours, though can occur everywhere in the body, if they occur in the inguinal region they may present sometimes like an inguinal mass [8], making diagnosis and differentiation difficult from inguinal hernia especially by inexperience hands. Hernia is readily distinguished from inguinal masses by by its characteristics of reducibility, cough impulse and reproducibility. Most classical neurofibrosarcomas consist of tightly arranged spindle cells, which are often densely distributed around blood vessels in loose or mucoid areas; these spindle cells grow diffusely in rich intercellular areas that are interlaced with cell-sparse areas. The cytoplasm is lightly eosinophilic or dichroic [3]. The nuclei are darkly stained, irregular, and contain obvious mitotic figures. Approximately 1/3 of neurofibrosarcoma are composed of large cells with obvious pleomorphism and common multinucleated giant cells [3]. Due to the lack of morphologic specificity of tumour cells, it is difficult to distinguish them solely by microscopic features. Therefore, further diagnosis requires a combination of immunohistochemical staining and microscopy [5]. In one large series, a total of 159 patients with neurofibrosarcoma were enrolled in the study. The ratio of male to female was 1.04 to 1. The median age was 40 (range: 5-76) years at the time of diagnosis. The 3- and 5-year overall survival rates were 50.0% and 43.0%, respectively. The median follow-up period was 31.0 (range: 2.0-199.0) months [9]. This is consistent with our index reported case.

Conclusion     

Neurofibrosarcomas are very aggressive peripheral nerve sheets tumours that present diagnostic as well as therapeutic challenges. There have variable localisations and clinical presentations. Their clinical presentation in the groin may mimic inguinal hernia. A high index of suspicion is therefore needed in the evaluation of all patients with groin masses to rule out all other causes which may not be related to hernia.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

ASNM and PT conceived the manuscript; MLO, OA, LNO, JCF, FE, PJF, FA and MAS corrected the draft manuscript. All authors read and approved the final manuscript.

Figures     

Figure 1: ulcerating and fungating groin mass at presentation following two repeated inguinal explorations by the primary care physician

Figure 2: showing groin after complete excision of the mass at Douala Laquintinie Hospital

Figure 3: cytology showing cells suggestive of neurofibrosarcoma

Figure 4: recurrence of the groin mass a month after excision at Douala Laquintinie Hospital

References