|Year : 2022 | Volume
| Issue : 6 | Page : 756-759
Infantile myofibroma: A report of two cases with differential diagnoses
Soumya Dey1, Bappa Mandal2, Uttara Chatterjee1, Suchandra Mukherjee2
1 Department of Pathology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
2 Department of Neonatology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
|Date of Submission||20-Jan-2022|
|Date of Decision||28-Feb-2022|
|Date of Acceptance||26-Mar-2022|
|Date of Web Publication||11-Nov-2022|
Department of Pathology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Infantile myofibromas (IMs) are benign soft-tissue tumors of children. They are of fibroblastic–myofibroblastic origin and show considerable morphological overlap with other spindle cell neoplasms. Here, we present two cases of solitary myofibromas, one in a neonate and one in a 2-year-old girl. A 2-day-old girl presented with severe respiratory distress and died during intubation. At autopsy, a myofibroma involving the oropharynx with extension up to the larynx was noted. Second case was a 2-year-girl with a myofibroma in the hard palate. IM must be differentiated from other benign and malignant spindle cell tumors of infancy and childhood. Oropharyngeal myofibroma should be considered in the differentials of neonatal respiratory distress.
Keywords: Congenital tumors, fibroblastic–myofibroblastic tumors, infantile myofibroma, oropharyngeal tumors
|How to cite this article:|
Dey S, Mandal B, Chatterjee U, Mukherjee S. Infantile myofibroma: A report of two cases with differential diagnoses. J Indian Assoc Pediatr Surg 2022;27:756-9
|How to cite this URL:|
Dey S, Mandal B, Chatterjee U, Mukherjee S. Infantile myofibroma: A report of two cases with differential diagnoses. J Indian Assoc Pediatr Surg [serial online] 2022 [cited 2022 Dec 7];27:756-9. Available from: https://www.jiaps.com/text.asp?2022/27/6/756/360947
| Introduction|| |
Soft-tissue neoplasms are common in the children compared with adults and differ from adults in their histological spectrum. The benign spectrum is extremely wide and diverse. The diagnosis of these tumors can be difficult due to overlapping morphologies. Infantile myofibroma (IM) or myofibromatosis is a common fibromatosis of infancy and childhood. Almost 90% of cases present within 2 years of age and over half are congenital., IMs are frequently underdiagnosed as it shows considerable morphological overlap with other benign and malignant soft-tissue tumors of childhood. Here, we describe two cases of IMs.
| Case Reports|| |
A 2-day-old girl came to our hospital with severe respiratory distress and stridor. Urgent intubation was tried and the procedure proved to be difficult. During manipulation, massive bleeding started from the surface of the mass obstructing the airway and the baby eventually died. At autopsy, oropharynx was full of blood clots and a large hemorrhagic mass measuring 3 cm × 3 cm was noted in oropharynx and extending into hypopharynx and larynx. Mass was excised and microscopic examination showed features of a spindle cell tumor with central dense and peripheral hypodense areas. Central dense areas consisted of plump spindle cells arranged in a hemangiopericytoma-like pattern. The tumor was seen to infiltrate into surrounding skeletal muscle fibers and entrap mucous glands. Immunohistochemically, the tumor cells were positive for smooth muscle antibody (SMA) and negative for desmin, myogenin, CD99, Bcl 2, S100, and CD34 [Figure 1] and [Figure 2]. On basis of these findings, a diagnosis of IM was made.
|Figure 1: (a) Gross photograph of the specimen showing grey-brown mass in hypopharynx and larynx; inset shows hemorrhagic mass in oropharynx behind tongue (b) Scan power view of tumor with laryngeal muscles and thyroid cartilage, (H and E, ×40) (c) Low magnification showing biphasic pattern of tumor with entrapped pharyngeal glands (H and E stain, ×100) (d) Low magnification showing tumor and adjacent thyroid gland (H and E stain, ×100); inset shows high magnification view of the same (×400, H and E stain)|
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|Figure 2: (a) Low magnification of tumor showing central hemangiopeicytomatous areas (×100, H and E stain); inset shows low magnification of the same tumor with characteristic zonation (H and E stain, ×100) (b) High magnification of tumor showing plump oval to spindle cells arranged around one vascular space (H and E stain, ×400). (c) Low magnification showing desmin negative tumor along with immunopositive muscle fibers (×100). (d) High magnification of tumor showing patchy SMA positivity (×400)|
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A 2-year-old girl presented with a mass in the hard palate for 6 months. Computed tomography scan of the oral cavity revealed a heterogeneous mass with increased vascularity and a diagnosis of soft-tissue sarcoma possibly rhabdomyosarcoma was suggested. On excision, a poorly circumscribed mass measuring 3 cm × 2 cm was identified. It was a tan-colored mass with hemorrhagic areas. Microscopy revealed a tumor beneath the squamous epithelium, consisting of plump oval-to-spindle cells arranged in hemangiopericytomatous pattern. The peripheral areas had loose spindle cells. There was no evidence of increased mitosis or cytological atypia. Immunohistochemistry showed negativity for desmin, myogenin, CD 34, S100, and patchy positivity for SMA [Figure 3]. On basis of these findings, a diagnosis of IM was made. The child is doing well on a 4-year follow-up.
|Figure 3: (a) Scan power view showing Overlying squamous epithelium and a tumor beneath it (×40, H and E stain) (b) Low magnification of tumor showing hypocellular areas in top right corner and hypercellular areas in bottom left corner (×100, H and E stain) (c) Low magnification view showing plump ovoid-to-spindle cells with hemangiopeicytomatous vessels (×100, H and E stain) (d) Low magnification view showing hypocellular areas consisting of loose spindle cells arranged in fascicles (H and E stain, ×100) (e) High magnification view showing both cell population (×400, H and E stain) (f) High magnification of tumor showing smooth muscle antibody positivity(×400)|
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| Discussion|| |
Soft-tissue tumors are one of the most common tumors of the pediatric population and account for 7%–10% of all pediatric tumors. They cover a spectrum of benign, intermediate, and malignant neoplasms, although the most of the cases are benign. Although benign in nature, many of these lesions show high cellularity, mild atypia, and increased mitosis, making them difficult to differentiate from other malignant lesions. Immunohistochemistry is an essential adjunct in soft-tissue tumor diagnosis but many of these tumors do not express specific antigen and show variable and overlapping expression.,
IM was first discussed by Stout in 1954 as “congenital generalized fibromatosis,” and was later termed as “infantile fibromatosis.” IM, a common fibroblastic–myofibroblastic tumor of infancy, presents as solitary or multiple masses involving the skin, soft tissues, bones, or internal organs. It commonly affects the head and neck region of infants and young children, but can also affect adults. IM is classified into three clinical subgroups: (1) solitary IM; (2) multiple IM without visceral involvement; and (3) multiple IM with visceral involvement. In approximately 30% of IM cases, the lesions are multicentric and arise not only in the skin and soft tissues but also in the bone, lung, heart, and frequently in the gastrointestinal tract., IMs show equal sex predilection. Radiologically, IMs can be heterogeneous, poorly circumscribed, and show high vascularity. These features can lead to misdiagnosis as hemangioma or soft-tissue sarcoma of childhood.
The distinguishing histological feature of IM is the biphasic growth pattern. The plump spindle cells with tapering ends, present in the periphery are of myofibroblastic origin. The central zone is composed of primitive ovoid/spindle cells arranged around blood vessels in hemangiopericytomatous pattern. Histologically, IM needs to be differentiated from other spindle cell neoplasms of childhood. The common differentials of spindle cell tumor of infancy are fibrous hamartoma of infancy, infantile fibrosarcoma, lipofibromatosis, spindle cell rhabdomyosarcoma (RMS), primitive mesenchymal myxoid tumor of infancy, solitary fibrous tumor, nodular fasciitis, giant cell fibroblastoma, angiomatoid fibrous histiocytoma, and synovial sarcoma. As all these tumors show significant morphological overlap and immunohistochemical (IHC), markers are often used to distinguish them. It is evident that immunohistochemical methods also have a limitation due to overlapping expression and no single marker alone can reliably be used to validate the presumptive diagnosis.,, Immunohistochemical features of IM are not specific. The tumor cells are vimentin and SMA positive and negative for CD34, S100, desmin, Bcl 2, and CD99., In the recent WHO classification of soft-tissue tumors, 2013 and 2020, IM has been grouped under tumors of pericytic origin.,
The common causes of airway insufficiency in newborn are congenital malformation of craniofacial bones, pharynx, or larynx. Rare causes are anterior meningomyelocele, nasal glioma, nasopharyngeal teratoma, RMS, hemangioma, and rarely myofibroma. So far, only three cases of myofibromas as extensive as to cause airway obstruction are described in the literature.,, In our case, the mass involved the oropharynx and extended into the larynx close to thyroid cartilage to enclose laryngeal muscles and glands. Although benign in nature, due to vast extension and infiltrative pattern, complete excision is very difficult and these IMs tend to recur.
PDGFRB mutations have been identified in autosomal dominant myofibromatosis and sporadic multifocal varieties. IMs may regress over time due to tumor apoptosis or contraction of myofibroblasts. Small tumors are treated by conservative approach, whereas huge tumors usually need surgical resection. Inoperable tumors have been empirically treated with chemotherapy, vincristine, and actinomycin D.
| Conclusion|| |
Diagnosis of IM can be challenging because of morphological similarity with other spindle cell tumors of childhood. Careful assessment of histopathological features along with supportive immunohistochemistry is important for making the correct diagnosis. Oropharyngeal myofibroma should be considered a differential of airway obstruction in newborns and watchful microlaryngoscopy is needed to avoid any catastrophe.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]